Why do we want to distortions?

"...That was one way out wacky theory kijanki..."

No it's not. Distortion, at a certain volume level, is an clue to loudness, if you can get that clue at less than extreme levels your brain thinks you are at the limit and really rocking. In the home environment, that's a good thing. If you have a huge room to fill and need to really crank it up, early distortion may be detrimental. I listen at low volumes, so tube amps give me that live music experience that I seek. YMMV.  

I have never measured amps, I just buy what sounds good. Don't really care about anything else. 

"...Distortions make sound more dynamic and often we want them for this reason..."

This is the real reason. Good summary.