Before we go any further, a word about pricing. The Lumi Keys costs $299, which includes the 24-key keyboard, a case, and a year of Lumi Complete (the full collection of songs, lessons, and exercises) in the accompanying app.
If you want a second keyboard, you can't currently buy it without the software, so it'll cost you another $299.
After a year, you'll need to buy another year of Lumi Complete for $79 (400+ songs, 130+ lessons, 380 exercises, games, and new content each month).
Alternatively, after the first year, you can keep using the free Lumi Essential portion of the app (40 songs, 60+ intro lessons, 72 exercises).
"Lessons" involve an on-screen instructor and step-by-step guidance where you play along with what's on-screen. They're great for absolute beginners.
"Songs" are divided into three activities: 'watching,' 'practicing,' and 'challenge.' The first shows you what to expect, the second lets you slow the track right down to learn it, and the third sees you play along in real-time and get graded on your accuracy.
You can display the notes to play in four different ways (including as regular sheet music), but one major omission is any recommended finger placement.
In the unlikely event you burn through Lumi Complete's hundreds of songs and exercises, you can even use the keyboard with other dynamic learning apps like Melodics.
We know because we tried it. (Officially, Melodics only supports Roli Blocks and Seaboard, so this is a score).