$10 for something that (I think) doesn't work on most phones but isn't gated to ones it works on feels hostile.
Probably there's no way to gate, in that case I'd suggest not charging for it. Or I guess adding a daily usage limit that's lifted with an IAP.
I'll admit I was off-put by the price to begin with, which probably amplifies what a slap in the face it feels like to pay and get something that doesn't work at all.