I think op meant the custom songs, there are thousands of them, amoung which a lot are of very high quality gameplay wise. I've been playing beat saber since when it came out (so about 7 years I'd say), and while I do play an "official" song here and there, most of my playtime is on customs. While this custom content does play in their favor, they do not however make it trivial to access it (you have to mod your game, which is a bit involved on a quest headset), unlike some other games, so I guess a lot of buyers don't actually buy the game for the custom content