First of all, many people debate whether perfect pitch can be learned after the age of about 6. But there is a decent amount of literature claiming otherwise, and at this point one could find there is a trope to learning it as an adult. One of the main tenants of any practice of it, though, is constant, regular, long-form practice. Like, daily 30-minute intent practice over 10 years.
That said, Tone doesn’t do that, at least not in its methodology. Maybe it could work with regular, 30-min practice over many years, but Tone isn’t robust enough to incite that sort of commitment out of it.
As it is, it’s an excellent relative-pitch practice device. The main issue is that, once the user hears the first pitch of their practice session, the rest of the pitches from that point on are heard in relation to the first one — thus ‘relative’ pitch. The only way this could really be used for perfect pitch practice is to try at only the first pitch when you open Tone , then put it away for 30 mins, listen to other stuff, then come back and try it again, over and over and over.
FWIW, it IS still really great as an on-the-go ear training gismo. I’ve already thought about having my students use it, as it is very simple but has many options for scales etc.
I have my doctorate in music composition, so I think about this stuff a lot. Thanks for Tone regardless!