We run out of time to play.
It's not 'serious' or 'necessary' (but believe me a world without it would be horrific!) vs other things like going to the office or doing your accounts or hoovering the floor or making the dinner...
It costs money to buy materials, it is hard to justify that sometimes, particularly if it is simply to play with them and see if you like them, which is the only way to find out if you're any good or if you enjoy them.
Im not overly big on formal education, but school is one place where kids will get access to materials that may not be available at home (absolutely KICKING myself for not making use of the school kiln when I had the chance!) and encouragement to be expressive and try things out. Try to get them to make the most of it!
We get bogged down by worrying about purpose 'what is this for, who is this for, why am I doing this'. Do it because its nice, it gives your brain time to relax, because you like the way the pen feels or how the paint blooms on the page!
Its a ton of boringly adult, miserable reasons, and the fact that people now think they can just AI an image rather than pay someone to create one, or want to put up 'original prints' from a run of 100'000 available on Wayfair, and think its just fine that places like Wish and Temu and even big brand stores happily steal actual artists work because it's only images, it's not like stealing a purse or a car... that stops parents pushing kids to do art as a serious thing.
And whilst I am on a rant..
For fucks sake don't squash kids creativity by getting on at them about tracing or copying.
Kids want to see results, without rapid success that pleases the eye, they give up.
Kids haven't the hand/eye co-ordination, the fine motor skills, the understanding of depth, perspective, colour value blah blah etc etc... to instantly be good at taking whats in their mind and putting it on a page.
Letting them trace and copy lets them get those pleasing results fast, which encourages them to do more! As long as they understand the difference between copying for practice vs original work, that's all they need know (and broach that in a kid appropriate way!).
There is a lot of skill in accurately copying other peoples work - Disney and Warner Bros cartoons are built on it, people working there spent (And still spend, though typically digitally now) weeks and weeks learning how to all produce Mickey and Minnie and Bugs and Wile E. Coyote et al, the same as the person next to them, so that everyone could work on the same cartoon.
If you want, you can find the character stylesheets online, and show them to kids interested in cartoon characters and how they're designed and drawn.
I started by copying, tracing, learning how to draw Marvin the Martian and Thelwell Ponies and the various line drawings in pony books, the art that was around me day to day.
If the old masters did it (and boy did they!) then your 6 year old can do it too - even when I do a commissioned pet portrait, I may well trace some elements - if I hand draw the whole image to start with (I do if theres not a single quality ref. image to work from, but it adds significant time which the client ends up paying for!), I still then transfer it to the surface using tracing, because I draw well on paper, but drawing on Pastelmat or Mi Tientes velvet with a fine pencil isn't very nice to do (for me, personal choice!) and errors are hard to fix!