I think it could be. E.g. when making a low-cost consumer appliance. They must have had some idea of what they were building, enough to say that the upper bound on the number of buttons they need is N. This just creates a design constraint - they now have to figure out how to do something useful and ergonomic using no more than N buttons. The exact shape, form and placement of those buttons is orthogonal to the electronics and software part, so they didn't limit themselves there.

This is unusual to my taste, but thinking about it, I half expect cheap appliance and toy vendors to work like this - decide on a microchip, and only then figure out what to do with it and how.

Looking at almost any car, even in recent years, you will see blanks for features that may or may not be present, that need buttons if they are there. They may be more obvious on some cars than others, but even luxury cars have them.