I used to own a BOSS expression unit. It was sold off due to under-utilization. Actually, the big footprint was a put off as well. The EV-30 here is a more compressed version that promises some estate saving on your pedal board.
More importantly, it has a dual output function so you can manipulate 2 pedals in a single use so that's the winning feature right there. The expression pedal is perhaps one of the least exciting unit with many pedal geeks but those with years of pedal use experience would tell you that over time, you tend to look forward to subtle sculpturing of tones rather than setting everything to 10 & let it rip. So the moral of the story here; it might be boring but it's useful.