Because it's culturally tied and thematic to existing races. It's exotic but not OP on the level of Titan technology in the lore.
But who are you marketting this to? If they put Tinker on the big screen at Blizzcon, and they say they're using Titan technology, then they better have a rock-solid concept behind it all. Otherwise it's a shallow concept in and of itself. I'm not looking for Nano-suit Ironman Tinkers.And again, Titan technology is not magic. Calling it something it's not over and over again wont change that fact.