At least for me - friction. That said, this is definitely targeting more of the DP market (with built in sounds), since if you're using a midi controller like an NI Komplete keyboard you already have to connect DAW/VSTs.

Having to lug my laptop out, boot'up Bitwig, connect it to the piano, press record completely takes me out of the flow.

With this, I can flip on my Kawai and start banging away, then pull out the impromptu motifs for later refinement.