Short answer: yes, cooperatives are extremely useful.

Long answer: cooperatives can be used as a way to test how a socialist/communist workplace could possibly look like, while at the same time bettering the conditions of the workers, and is a great way to both democratise the workplace and at the same time build a framework for when a socialist revolution occurs. Though obviously under capitalism cooperatives are limited in what they can do, they still need to make profits and play along with the system, so basically making the workers take the place of the capitalists, so they by themselves aren’t going to initiate a revolution or inact socialism, but it is objectively better for the workers in the meantime, and can be analysed and observed to prove that people can run the nation themselves without the need of class hierarchy. As for why they aren’t widespread: my theory is it’d obviously upset the bourgeoisie (as well as possibly posing a threat to them with the people gaining more power in the economy) if every single business was a cooperative, they want all that wealth to themselves, same reason as to why social democracy never works in the long term, especially if it starts gradually veering more to the left then it’s supposed to, anything that benefits the people too much at the expense of the bourgeois class, will be gotten rid of as quickly as possible by the wealthy by any means necessary, the only time it’s left be is if it isn’t a threat to the bourgeoisie, so a single cooperative or two in a city/town, isn’t gonna do much in the grand scheme of things, even if one of those cooperatives is very successful, and so the wealthy leave them be. There’s also regional differences, some places are unfortunately more individualistic or tribalistic/campist and so cooperatives are going to struggle a lot more in those regions, some governments simply don’t allow cooperatives or any form of democratic workplace to begin with, cooperatives can be very difficult to start in most areas - either due to larger companies being nearby or due to bureaucracy, most people haven’t even heard of a cooperative or how it works, the international media rarely talks about them - and if they do it’s quite brief and suger coated in liberal language and so nobody really pays attention to it, etc. but other then that I’m not a hundred percent sure. As for the internet and Blockchain aiding the growth of these policies: yes, the internet especially so, and as much as I dislike crypto as a whole for what it stands for - and being a capitalist tool for the vast majority of the time, I do realise it serves a purpose under our current system. It’s permissionless, open source, community run (for the most part), and in the case of Monero as an example, it’s anonymous and somewhat power efficient compared to other cryptocurrencies, as well as being able to run on most computers, so it can be of benefit to let’s say, people living in dictatorships that are hellbent on opressing anyone in regards to banking for whatever reason, or surveillance states as another, and can also be used to fund “risky” - possibly revolutionary - organisations without the governments or large banks being involved and seeing that transaction, or in this case, aiding a cooperative to be even slightly more public owned by using open source software and community ran Blockchains instead of the banks. There’s also other uses I can list off, but they’re more general and less important to a socialist movement in comparison to unions and cooperatives and parties, so that’s the general gist, crypto and Blockchains are very much a capitalist tool, built under a capitalist system, and predominantly contributed to and invested in by capitalists (especially if we’re talking about the larger cryptocurrencies, like Bitcoin, Ethereum, etc), but for certain people it can be quite useful - sometimes immensely useful - and can possibly aid socialists to some extent with it being community run, permissionless, and open source, so it depends on the context and circumstance mostly. And the internet is an obvious one, especially with services like the Fediverse and Matrix, End to End Encryption helps with privacy, running you’re own server helps with privacy as well, as well as not relying on a giant cooperations permission to host certain data/content, chats, people, etc. decentralisation can help with delaying buyouts, although not entirely prevent it long term, it’s only a matter of time before at least half of the Fediverse gets bought out by capitalists and companies, and open sourcing something is always a good thing, and gets people involved, as well as trusting the service more. The internet allows transfer of knowledge, ideas, conversations, and cooperation/planning across the entire world in almost an instant, and I’m not even mentioning all the other benefits the internet can bring, especially if it’s run by the people, so it’s extremely useful for any form of socialist movement. These all can help in the daily lives of people, which I’m always for, but none will do much in the long term if not apart of a larger movement, and most progress through reform and gradual change always gets rolled back one way or another with time anyways, so these ideas must not be the be all end all of it. I probably missed somethings but - I hope my thoughts added to the conversation just a little bit. Happy may day comrades! ✊