No algorithmic suggestions and therefore, no curated daily taste playlists, no sorting your library by genre (at least not as granular and specific as Spotify unless you put in as much work as they do at tagging your music), finding new music manually takes at least 10x more effort and you're limited to the taste you already know you have. If you switch phones you're SOL unless you want to deal with the insanely slow transfer speeds of androids MTP or whatever apples slow ass transfer protocol is. Not to mention your library is limited by how much space you have. My 10,000+ song playlists on Spotify aren't gonna easily fit on anyone's device, and definitely not at the highest quality that Spotify can stream at. Your only hope of getting even a comparable experience is to be tech savvy and patient enough to set up a home streaming server, manually tag all your music, and find an audio app with an interface/features that you like that also supports streaming. Oh and then your home computer needs to be on all the time, and your Internet has to be great, and you must not care about your energy bill that much, and ... I'm just gonna stop. Locally stored music is just not anywhere near as good. It's lame and tedious and nearly pointless. At most, I'd say keep a couple albums you like with high quality FLACs but that's it. You're waisting your time not getting Spotify premium or Apple Plus or whatever the heck
Oh and this is coming from 20+ years of pirating media. Limewire used to be the best, but now it's firmly Spotify etc.
You don't know what the word regular means. It does not mean acceptable or morally correct. It's synonyms include "standard", "usual", "typical" etc. It does not imply anything other than that. Dairy milk is the usual, typical, standard substance that is referred to as "milk" by 99.9% of the English speaking world.