They'll likely need to put something comparable to the iPad M2 in there to manage heat. That iPad M2 has about 1/3 the performance of my MBP M2.
Add in the fact that you're rendering a spatial world and you quickly have a lot of resources tied up.
I also think that if this were a feasible use case, apple would promote it. They are clearly positioning this headset as adjacent to the dev space, based on price and how they previewed it. And Apple is one of those companies that if you find yourself swimming upstream against how they want you to use it… it might be reason to find a different platform.
Add in the need to render a very large virtual space and you end up with a lot of capacity being used by default. That's likely fine for "iPad like tasks" (web-browsing, email, messaging), but it seems insufficient for anything requiring processing or memory.
It's not a family. It's the exact same physical chip. You can also check Apple's technical specs too. They are both listed as "8-core CPU with four performance cores and four efficiency cores".
The only real difference between the ipad, macbook air and 13" macbook pro is the cooling solution. The ipad is fanless and the macbook pro has a fan. If you had a longer-running benchmark, or a sustained workload you would see a larger difference, but not that large.
Development, Design, Video Editing, etc, etc still require additional capacity than what the Vision Pro is offering.