Oh I don't do that for that, there's multiple reasons, but one of the bigger ones is to promote smaller instances because of the volume of posting it makes smaller instances more recognizable.
Other reasons for the multitude of accounts include making comms on fitting smaller instances (I make programming related comms on programming.dev or retro related on retrolemmy for example), protecting against the imposter problem and better interconnecting wayward smaller instances (you'd be surprised at the number of, even common comms, that smaller instances are missing out on that I discover just through my posting)
We're supposed to fold those? Lmao I just roll it up