this is my first elektron device.... I really regret that I havent used any of them before... super powerful, live-playable, very well designed device.
Besides its own sampler, any of its 16 tracks can be a "MIDI machine". So, in this mode it does not produce any sound, but sends MIDI. And you can use any software synths on iPad (like Model D, Model 15 etc) with sequencer from Digitakt. But also, you will be able to easily map 16 parameters for each synth, and change them by Digitakt's knobs, and give names for these parameters, so name is shown on digitakt display....
I think it is the best instrument/device/tool/toy that I bought in last 15 years :D