It’s great for weird, emerging and receding echoes?
The most useful control button was added in an update a year or so ago, the ‘randomised settings’ button. It’s below the two shown in the screenshot pics in App Store, not shown in those pics. The parameters are many and varied, so in order not to need to become an expert on them, that button helps. One notable addition would be a bpm/sync option? Just about every delay has this, and it would make a lot of sense here, too, although probably require some ‘standard’ and even non-standard settings, 1/64 up to 2/1 or something? That’s my only useful input really, because one method of using delay/echo is to create multiple tracks where instead of making a sequence on one track, then a different one on another, a few brief notes can be input then they just echo forever, or at least a very long time. To do this requires some kind of feedback loop limiting to stop the inevitable ever-growing signal that I at least get when cascading echo/delay FX, to avoid damage to speakers or ears. Once this is in place, with a GarageBand DAW or any DAW, you could experiment with the random feature, or the manual editing, and it opens up another side to ambient music creation solely based in this app. Of course, the Developer may already have considered this and there could be deeper issues trying to do this in practice, but that’s my 2p/2c worth.