All of it comes down to how far you want to go. It’s a much bigger lift to go premium steel on once per week skating. I firmly believe that a peewee, at least at a higher rep level, can tell the difference - though articulating it is a challenge. They’ve been skating long enough (7-9 years), and let’s face it, the kids today can execute skills that we (the older generation) weren’t even aware of when we were their age. You definitely don’t need it to play well, but will the better edges allow you to execute skating skills with better confidence, probably.
pros of premium steel
added height - last longer, better angle on sharp turns without bottoming out
edge retention - less dings, dents, lost edges from board battles and other stuff
less sharpening required
Cons
cost, especially with growing feet
Again, your mileage may vary. Maybe my experience was excessively coloured by the steel used in youth skates, but I didn’t need a micrometer to notice an improvement.