There's a youtube video linked from the github that goes into some explanation into the "why", e.g. we should minimize deps, use standards instead of framework silos, avoid frameworks which have monopoly on dom, easier debugging, onboarding, etc. I agree with most of that in principle, I just don't know if this is the solution.
When we had larger component frameworks built on vanilla JS, like ExtJS, they had their own problems, e.g. framework code which alternated reading styles and updating styles from DOM causing reflow, or DOM listeners that were not properly cleaned up. But with those older frameworks, when something went wrong, it was trivial to debug the entire codebase including the framework, because it was all basic JS.
These days with something declarative like Vue, there's far less need to reach for a debugger and usually stuff just works, but when something does go wrong it's often a bit perplexing and you feel you're stuck because everything is happening in the framework black box. I still like Vue, but I must admit even if it's one of the simpler frameworks, there's a bit of an onboarding issue. I still see our devs making mistakes like doing side effects in computed variables, or modifying props state in children, even after a few years of experience.