@encarsia Techmoan recently did a video on 2 digital pocket thermal printers designed for kids, the #PeriPage and #MiniBear (of which the latter also had a built-in camera). Not the same as you are looking at, but it might give you an idea to the quality you can expect from the budget ones aimed at kids.

VTech is a more established brand, so I would hope the quality is better. :)

Still, something with a built-in printer might be a nice addition as they can immediately see and use the result. I also believe the greyscale thermal printer rolls are fairly affordable compared to the full-colour polaroid style instant printers.