I both love this and am horrified. It looks like it'd turn a Pro Max into a 9 inch tall phone. Since it's a case, you'd need a new one each phone upgrade. (I used to do this with the Apple battery cases, until I came to my senses and/or magsafe.) Although, I still occasionally long for the blind accuracy of the old Blackberry keyboard. I think I'd prefer an adjustable magsafe attached keyboard that can do either land…
I wonder if a magsafe secured, size agnostic version could be made. Less locked in but easier to split across pockets and possibly works for more than one model.
This certainly must have been an option they explored. Without a case secured to the body of the phone, pushing the keyboard buttons would probably pop off the magsafe connection. There's a lot of leverage on those clicks.