One thing Roam does very well is allow simultaneous edits to different blocks, even in the same page, to be automatically merged.
From the latest announcements, it sounds like Logseq Sync is aiming for a simple last-write-wins sync model. This can be fine – last write wins for competing edits to a single block is totally reasonable – but if the granularity is whole Markdown files (or a whole edn file), it is very dangerous.
The daily note, in particular, is constantly being updated everywhere. If the mobile client has slightly stale data when you launch it to quickly type a new note (as a new block underneath the existing content), it is very important that that be able to seamlessly merge without clobbering other notes written as other nodes elsewhere.