Each to their own I say. Isn't that the idea of freedom of choice?
Three of my (adult) kids out of five smoke weed for recreational use. It does niggle me a little that it tends to make them procrastinate a fair bit, apart from that I don't see a problem.
Everyone has some kind of vice, something they like to do for fun and to relax. I would much rather my kids smoked weed than took something stronger, more addictive.
After having an alcohlic mother and still having an alcohlic brother, I think drinking can be and is far worse. It also can make people much more argumentative and aggressive which, personally I've never heard of with cannabis.
Even though it's not legal in my country. I am 'glad' if you like, that my kids have chosen cannabis over alcohol.