The primary benefit coloured stickers seem to have would that it allows extremely low-effort police fishing-- wrong colour plate corner, great excuse to hassle someone in the wrong neigbourhood/car/skin colour.
It maybe made sense back in 1970, back when there was no easy way to validate a plate in real-time. But today, I'm assuming that in any meaningful traffic-stop interaction, they phone home to check the plate before even leaving the cop car, to confirm it wasn't marked stolen or in an Amber Alert style scenario. Adding on "is this plate current, and should it be attached to a Hyundai Sonata according to registration files" is an obvious extension. I'm assuming they have the bandwidth and connectivity to pull that off.
Then you save all the cost of mailing out and managing stickers, and the wasted police effort chasing people who are waiting for them in the mail/had them damaged.
Ignoring my snark in a comment above, the one real benefit is someone can’t easily steal your registration sticker. They’d have to steal the whole setup.
Sticker theft isn’t a thing where I live (that I’m aware of), so that leaves me personally without a single benefit besides the idea appealing to me for being “neat”/“techy”.
Which doesn’t begin to compare with the problems. I’d be iffy/worried if this was a 100% government thing. The race a private company is involved/started it is so much worse.