Are you building [Ice Skates] or are you building [Ear muffs]?
Ice skates allow you to do something new that you didn't even know you had a demand for. Ear muffs solve a problem that you were already solving poorly (with your hands).
[Business vs toy] is an insanely counterproductive mental framework which will create a false sense of security in founders who are actually building crap - just because you can play with it does not mean it has value.