Yes, I agree it is nice for those where size is important. I also don't mind paying for upgrades. I did way back with Line 6 years ago with the XT Live. For me, the combination of the hardware plus upgrades, priced it out of interest to me. Not that it is a very good comparison at all , but Boss managed to put their entire flagship modeler in the Core for $600. Although a very different device, it is a very nice pedal. I bought it instead of the Player when the Player was first released. Also in my case it is something extra that would have been nice but do not feel the need. I agree that it is awesome Kemper did this for those that have the need, and it is really cool they fit all the upgrades in a much smaller format.
I owned the Boss for a while and while it’s a cool unit, I wouldn’t put it in the same category as the Player, other than they are both small. Kemper sounds so much better IMO.