My disconnect is I can't read sheet music. So I can hear it, then memorize where it is on the piano/keyboard... but that just teaches you play piano by ear. It doesn't teach you how to play music in the traditional sense.
I guess this showing you the sheet music as you find the notes can help with that, but as others noted - I'd like a "mess around" mode, before a "test" mode.
I think it depends on your end goal.
I have a great ear and am terrible at reading sheet music. Fine if you aspire to be a rock guitarist. Not so fine if you aspire to be a classical pianist.
Funny, but I'm final tired of my poor sight reading and have set a goal for 2025 to average one hour of piano playing from sheet music per day.
And I agree...a "mess around" mode on the app would be great. Feels almost punitive when I make a mistake.