Garageband on iOS has some features which are useful for auto accompaniment - but you have to set up what chords you want the 'smart instruments' to have available, then you use some type of single finger entry while recording to pick from that set of chords for the duration of your single-finger action. Kind of like a Casio/Yamaha arranger keyboard with one-finger-chord action. So it's not BIAB, but it can be actually quite useful.

If you want live play capability, there's no choice - iOS runs circles around Android as core audio and core midi functions are part of the OS, nearly eliminating any latency. This is also why there are probably 1000 x more music apps for iOS than there are for Android.