I do have a blendtec I bought from Costco on this same deal few months back. It is awesome, but sometimes I wonder if it really has a practical advantage over Ninja which is around $200 cheaper if all you are doing is crushed ice smoothies etc.
You are right. If you don't use the blendtec to its full potential why spend the money on one? I for one own a blendtec and I do all sorts of things with it; cashew butter, tahini, hummus, grind flour, etc I couldn't be happier and use mine everyday.
If my needs for a blender consisted of making pina coladas a few times a year, I probably wouldn't have been interested in the first place.