it does matter, stable releases typically contain less bugs than nightlies. it doesn't mean bugs are nonexistent, but usually most of the known ones are fixed by a stable release.No it does not matter it's ignorance to only use stable releases as one example Luma3DS v5.5 has a bug saying u need to update when your already on latest fw
probably doesn't matter to you, but it does to someone else.
also, that bug was in 5.4 and fixed in 5.5.