Weather packs (all 3 of them) are free and are very hated with no one actually uses them.
Terrain packs are becoming BP exclusives, but many of them suffer the same problem as weather effects (bad FPS), so nobody cares about them.
Music packs (unless it is the music pack that comes with the BP) are never free, but you have to admit, some of them are really freaking good.
But yeah, Dota 2 Battle Pass should just be renamed to Kotex, since it sucks so much blood from the players. And they are doubling it with many “community-voted” Arcana tier items becoming BP exclusives that are also non-tradable.
Really scummy move Valve.