There are more 3D printers than useful applications according to a man who has been in the business an awfully long time. What do you think? #3Dprinting
I think this sentiment was expressed (almost in exactly the same way) when the personal computer first came out. “All these machines, which are no more than glorified calculator chips wrapped up to look like computers, and who is going to use them? What could a so called ‘personal’ computer do that the average consumer would want?” – Ken Olson, Digital Equipment Corporation (I may not be remembering it word for word but that was pretty much what he said)
That’s a good point @Chuck_McManis as Fried goes onto say the technology has plenty of uses but not all being showcased well at #CES2015
I think we can see enough useful applications. If we want to see it 
Produce spare parts for repairing your coffeemachine
To produce toys for your little boys and girls
You can use it for arts merchandise, or make little thinks for youre next party.
And on youre favorite hobby, its helpful to.
As its costs sinks it also revolutionized the professionals like scientists or designer and architects
When I was a little cuss, and aching to get a home computer, I told my parents they could use it to balance their checkbook.
About as contrived as making replacement parts for miscellaneous home appliances…but it begat tablets, iPods, Nests, Raspberry Pis.
I’m not saying that things will evolve to send email, then host web pages, then extrude plastic, but what these things end up being used for a decade from now is anybody’s guess.