Well, for one, classical music aficionados have always been significant in the music world (the CD format does seem to have been intended in part for classical, and most reel-to-reel sales were probably classical), making stuff easier for them helps establish a captive market. Two, as other people have pointed out in this thread, classical music differs from pop music in that composer is usually more important than performer (in pop music, you generally care more about getting a specific version of a song, that’s not really the case with classical music), and you’re far more likely to listen to a work straight through than to shuffle songs. So, from a discovery perspective, having an app tailored for classical music does make sense. Heck, there are a couple of music streaming services that focus just on classical, so there’s a market for the app.