[Holger]

Ummmm, the potential for addictivness is high. And I dont see any creative benefits.
I would NOT let a five year old play Minecraft. Or Clash of Clans, or anything like that!
My son plays Minecraft sometimes, but he is 13 and he has 1 hour computertime per day, AFTER the chores and school-items are done.

Get the app Monument Valley or something like that.
Or, buy Legos for Gods sake.
I have never understood why small kids have to be glued to a screen for hours other then that the parents wants to "mute" them.

Once you start using apps and computer the social contacts will vanish very fast.
Getting the small kids go out and play football or other things with friends is no option anymore.

Regarding playing online: the comments in the chats and bullying and strange people (pedos!?) contacting the kids is not avoidable.