I know that varies by region, but schoolchildren are generally taught cursive as a faster way to write. It already requires some memorisation with some glyphs being different from block letters. Why not make an additional step and completely replace it with shorthand, making writing an order of magnitude faster?
Being able to read cursive would be a second thing. Lots of old letters and texts written in cursive, and that can be hard to decipher if you’ve never learned it at least a little.
You can learn to read cursive without writing it at all
It’s certainly easier if you’re taught, especially at a young age though. I feel like when I was young and learned, that it wasn’t more than a week or two on the topic. I personally don’t think that’s a wasted effort.
In the sense that any deliberate sustained effort improves a person in some way I agree, but it’s almost certainly not going to be practical unless you’re going into a field that requires reading cursive for some reason. Making it a standard part of every education just doesn’t make sense anymore.
I think learning to read is just one benefit. As others mentioned, hand eye coordination is another big factor. I’m not opposed to not teaching it, just listing some benefits of doing so.