I discovered the game through an undertale map yt video, so probably yeah. That's then, if you talk about now.. well I don't watch anime anymore and I'm already too invested to mapping, so I'll stay.
There are plenty of amazing songs other than anime ones so I definitely would! I believe that if anime content was removed from osu!, there would be mappers who would work on even more non-anime songs, which is why I'd stay here, even if anime related maps dissapeared.