It seems that many/most brands of shake light are quite fragile and are basically toys. The Nightstar brand seems to actually be a decently made product from what I've read, although I've never handled one. That said, would I consider them a joke? Well, the cheap ones, definitely yes. The good ones--well, it's hard to find a good use for them. Their beams are narrow and quite dim and they don't run very long. In spite of their advantages, those disadvantages make them pretty useless for most situations unless you were Tom Hanks on Castaway or something like that.

But, for a child that likes playing with flashlights and who will tend to leave them on accidentally, why not? Then again, how about just using rechargeables in the flashlights they might play with?