Dyson spheres would require so much energy and material to construct that to be able to build one you wouldn’t need it in the first place. Dyson clusters are closer to doable
Really though, you’re right, the closest thing they’d ever be useful for is as stellar engines since you could theoretically make them have a lot more surface area on one side and they would slowly accelerate a star exerting pressure on the structure. So some kind of type 3 civilization could be moving stars around over millions of years.
Dyson spheres would require so much energy and material to construct that to be able to build one you wouldn’t need it in the first place. Dyson clusters are closer to doable
Counterpoint:
Really though, you’re right, the closest thing they’d ever be useful for is as stellar engines since you could theoretically make them have a lot more surface area on one side and they would slowly accelerate a star exerting pressure on the structure. So some kind of type 3 civilization could be moving stars around over millions of years.
I watched the text commentary for.that TNG episode with Scotty and Michael Okuda their art director and science guy explained it.