How could anyone imagine VAR would be useful, even if it was actually implemented intelligently?
As it stands we have an extremely imperfect system for calling or reversing decisions over the course of several days after the match. And we have a basic, but systematic, failure to even understand the basic principles around some fundamental aspects of refereeing a game:
1) What is a handball?
2) When is a dive, following minor contact, a foul?
3) And when is it a dive?
4) And when do you give a yellow and a free kick for a dive, when do you just ignore it?
5) Why are attackers in the box being punished by referees for trying to score by playing to the whistle?
These are just a handful of things that need to be clarified (and publicly codified with some directive or whatever). Otherwise we're just adding time, to an already diminishing spectacle (with timewasting endemic) to further ruin the sport. And showing contempt for people who attend football matches (favouring advertisers and tv spectators.
Either refs will close shop and collude with one another (see why you're referring this to VAR, and yep there's a dive there, but the ref was right so won't overturn it) or embarrassingly overrule each other constantly because even the same referee frequently calls things like handballs contrary to their previous calls (it hits his hand yes, but it was very quick and close to him vs it hits his hand and is very close to him, but i'm giving it anyway)