No, they're really not. Idagio, Primephonic... they're essentially the same thing with a different user interface: B-grade software apps made by classical music aficionados. I've been a subscriber to both in the past (at different times), and they're essentially the same thing and need some professional developer TLC.
And what's the point of them? I suppose it would be to replace the concept of buying and collecting CDs at no sacrifice to audio quality, and ultimately providing a cheaper but more permanent and organized experience. If it's $9.99/month that's less than the price of 1 CD per month, and still providing the digital booklet, CD quality audio, and library organization for all available classical recordings. The only thing that's missing is the sentimentality of truly 'owning' the CDs, which I admittedly would miss.
I also like the way that Idagio pays its artists: Instead of the way other platforms like Spotify do it by paying 'by the stream,' they dole out royalties by total seconds streamed. So on Spotify, a recording of Mahler 2 would make far less money than a recording of Robert Schumann's Carnaval, a piece with a couple dozen miniature piano movements. On Idagio, it's the opposite. I hope Apple takes heed of that.
My larger point, however, is that if a big company like Apple can take one of them and make it into something truly good, we might finally have something to seriously consider.
Let's just see what happens. It might be a game-changer, or it might be a cheap re-hash of these classical streaming apps we already have available. If it's the latter and Apple can't pull this off, then the old way of actually collecting CDs will remain the best way to experience classical music.