It's not about usable space. It's about the look. A smaller bezel doesn't lead to a better appearance by itself, but even then I'm sure they could've made the bezel smaller either way. However, the notch isn't made to be of minimal size. It's intrusive. It's telling me: I'm here, deal with it.
That space was black on the old MBP. It's black on the new MBP. I've now got two newly usable strips where the bezel used to be. The top menu bar is already left/right split, so it fits fairly naturally in there; my movies won't be any bigger or smaller with it.
I went from iPhone SE to 13 and the notch there was a nothingburger. Thirty seconds after the "oh right, there's a notch" it's mostly forgotten.
