I say this as someone that uses FOSS day to day for work, I don’t really give a shit if my Lemmy app is FOSS.
For me, Sync was Reddit. It’s where 99% of my interaction with Reddit happened. I don’t really give a shit about Lemmy or the fediverse either. I’m here because Sync is a seamless product that gave me the best interface.
Despite saying that I don’t care about Lemmy or other distributed servers, Sync is basically that sync (lol) for me. Once I map my old subreddits on Lemmy, the experience doesn’t change.