Haven't seen this mentioned in the forums yet, so I thought I'd bring it up:
Kobo closed all Kobo Kids' accounts on April 3, apparently due to low usage. Purchases made under the child's account have been automatically transferred to the parent's account.
https://www.kobo.com/help/article/6247
Going forward, if your child wants to read their Kobo purchases they must do so using the parent's account, and will have full access to the parent's library (and presumably, purchasing ability). Kobo has stated that they do not offer parental controls, but "we encourage parents and children to browse our kids and young adult catalogues together, to find their next great read."
My daughter is a voracious reader and asked for an eReader for her birthday (coincidentally, April 3rd). I debated between Kobo and Amazon - the Kobo Kids accounts appealed to me so that's what we did. I wish Kobo had given me some sort of notice when I created her account a few days before the 3rd... *sigh*