I think kbin/Lemmy is already showing promise as a community gathering-place, but it’s nowhere near useable for being a repository of knowledge like Reddit is - if you want to know how to download videos from an obscure local streaming platform in a small country, hear experiences of doctors treating a specific chronic condition, or find answers to a highly specific scientific question, a quick search with site:reddit.com would usually give you the answer, and if you didn’t there would usually be a relevant sub with someone knowledgeable in the field.

It’s going to take many years for kbin/Lemmy to reach this status of a digital Great Library of Alexandria (if at all), and so much information is still going to be lost if Reddit shuts down.