These looks like they could be fun and the app provide a lot of control that would have been hard to fit into such small machines otherwise...
Myself have been snared into toyland and have a small drum machine -tek.Drum and in the end got a Volca Bass for a good price second hand.
So it is nice to have these things around as they provide some inspiration.
How much they actually gets used in the end is something else...
Google Play:
play.google.com/store/apps/details?id=com.modalelectronics.craftapp