They prefer a more polished UI? I know there are several mobile apps that improve on the default browser experience of visiting https://lemmy.world/, but you have to admit that the initial UX of Lemmy leaves room for improvement. This is the same reason many open-source projects gave up on IRC. The die-hard FOSS advocates raised the "but Slack isn't an open standard" argument only to be shouted down by a larger part of the community with "IRC's UX sucks and is a barrier to new contributors".
https://kbin.social/ has a lot of issues (like calling communities magazines and general performance/stability), but the UI/UX is so much better than Lemmy.