Size *definitely* matters.
I'm using iPad Mini 5 today, quite old version of the current, top-notch models. I also have M1 Pro 13"(personal) and M2 Pro 14" (company) notebooks.
My daughter uses iPad Air to draw and have fun with it, and my oldest son has iPad Pro, the biggest model. When I compare both of these to my M1, I see that the size (and weight) is not *that* different. But (so far) when it's about typing, I prefer my M1. Yes, I don't have a "typing case" for my iPad Mini, but even if I had, I'd expect I'll still revert to the M1.
Today I'm ending up with bringing both :). Maybe, when it comes time to upgrade the Mini, I might move to Air instead, but primarily because I love how it acts like a second monitor for the notebooks.