Neo will at least help in ensuring that macOS doesn’t become too heavy for a few years.

Exactly, this is good news, it'll force them to keep 8gb in mind. It essentially restarts the clock on 8GB machines for the next five to seven years.

...hopefully.

That assumes Apple dev teams use one in their test suites.

One downside to the 11" Air when it was still sold is so much software that would be slightly broken on the vertically-constrained display.