In my opinion yes automatic or self cleaning cat litter boxes are worth the cost as it keeps the house smelling better, prevents the cat from tracking poop and litter everywhere and is easier to keep clean.
The automatic cat litter box I bought cost $500.00 but it works great and is the best $500.00 I spent on my cats.
Kittens can use a self cleaning litter box since the self cleaning litter box only activates once the kitten or cat leaves the litter box.
If the cat or kitten is transitioning from the old litter box to the new self cleaning litter box you usually need to put a bit of the soiled litter with the cat poop from the old litter box into the self cleaning litter box.
Keep the old litter box near the self cleaning litter box and allow the cat or kitten to choose which one they prefer to use and after about a week or two the cat or kitten may love the self cleaning litter box much better.
That's the way my cats did they now prefer to use the new self cleaning litter box and it's easier on me and keeps the house smelling better as well.