I'm really disappointed in this change - we use an internal extension in my company to quickly jump from one place to another, and this change means that all our internal users will have to re-learn this workflow - with the expectation some never will, since <tab> is quite harder to reach on most keyboards than <space>.

Given how obvious is the accessibility issue, and how silent was the change, it's hard to read it as a positive change when it's clear that the deciding factor is that it's been deemed better to have users unintentionally reach Google than the search engines they explicitly decided.