That's really tragic that people think like this. Not everything needs a "purpose", in fact many of the most beautiful things in life don't. Doing things for the intrinsic joy rather than for some end is a key to life actually imho. Those who must always do things with some future goal in mind, getting more money, power, stuff, prestige etc are missing out.

Ironically, tinkering for fun can lead to innovation. Many cases of this in maths, science and engineering.