We need to start maintaining winamp and the clones again.
When you are watching video, it's usually where your attention goes, whereas listening to audio is something done "in the background", while your attention is elsewhere (reading, writing, playing a game, or even cleaning the house).
Therefore to me it is obvious that an audio playing application should behave like a good butler - readily available when you need to e.g. change the playlist, but invisible otherwise - and I would compare a video playing application to a live entertainer.
A video playing application should of course also get out of your way so you can focus on the actual video, but there is a subtle difference nevertheless.
Also, foobar2000 is very well maintained, and implying it's not a good audio player is simply sacrilege!
I put lots of custom tags in all of the tracks I've ripped, downloaded, or recorded live, and I have yet to come across a Linux music player that allows me to search them or sort by them.
Clementine comes close, but not quite close enough. Maybe I need to get some Copious Free Time and rip into its sources.