Dengi’s BK9 plays all those audio formats directly from the USB stick (no loading time). It also has a built in mic input with reverb and EQ. It is GS compatible. And should you need something as crazy as running it with no power (honestly, who does anything serious musically away from power?) you can always run a power bank.

He already has an audio interface.

It would have been a total duplication of everything he already has (and a considerable step back in many areas). Had it have been a Yamaha or Korg module, I’d have said go for it, simply for the completely different samples for the sounds. But you’ve heard one Roland, you’ve heard them all, especially when you own the best ROM soundset Roland arranger ever made.