Because there’s more black and white behind the rules of cricket rather than in football where a lot of the decisions are up for debate.
And this is where we have the contradiction in football. It's only to be used to overturn decisions in instances of clear and obvious errors but this in itself is subjective. It works perfectly well for offsides (when the AR doesn't flag early) but as we have seen with the Madrid and City decisions in the last week or so, having VAR hasn't improved things in many situations.
We should look to other sports who've used technology for a long time to see how we can improve football VAR. Hawk Eye in cricket has never been 100% accurate, so they use the 'umpires call' to negate that inaccuracy. In rugby the ref instructs the video ref ie "can you give me any reason why I cant award the try" for example. Whether there's oppurtunity to introduce similar things into football is up for debate but I really struggled with the city decision last week, where if there was no VAR (and I'm.a fan of it!) Nobody would've batted an eye lid. Actually having VAR made that situation worse, particularly as the interpretation of handball differs across Europe, particularly in Spain..