The finding app has an arrow on it, pointing you towards the signal. So maybe the map has only building-level resolution, but once you're in the building you just follow the arrow until it says you're standing on it.
Tile trackers are accurate within +-90cm based on some empirical tests I did for using them to monitor my cat's activity throughout my house.
So Apple's +-30cm does seem to be a fairly major improvement, if true.
If the sound is muffled and you can’t hear it, this sounds like it could narrow it down to a specific room or maybe even area of a room. Which is a huge improvement.
I haven’t personally used a Tile before, but my impression was “you get what building it’s in, then have to search everywhere til it’s in earshot”