The 'old' blenders with the big glass jugs (traditionally called "liquidizers") are a drag to clean, heavy, and they suck up space. Plus, their motors struggle with large quantities or big chunks. Typically, during blending, the blended bits will accumulate around the blades and the rest of the fruit chunks sit atop that, safely away from the blade. You then need to stop, loosen the shizz, return, blend, stop, loosen shizz, etc.
The Nutri Ninja has a pulsing action at two intervals during it's blending cycle, so you don't need to stop, open, loosen stuff. It blends a while, comes to a stop for a second, then pulses the load upwards as it starts spinning again. It is really convenient.
Only problem is, you can't use it dry - so you can't use it to make bread crumbs from stale, dry bread.