I can see the attraction. From a young persons viewpoint, or even someone who wasn't able to land the career that could buy a house or even a mobile home, a $300,000 mortgage seems unimaginably unaffordable, and they see no need for 1400 sq/ft of space to hold all the junk that marketers get us to buy. While I am firmly on the home owner side, I fully admit there is way more waste and gluttony in this life style.
At no time in history did we occupy so much space with our homes and there really isn't a necessity for a 3 bedroom 2 bath house for one person or even two. The tiny house premise draws you in with affordable living, a quick to pay off mortgage, and the ability to contribute more of your earnings to experiences (big requirement for millennials). While I agree with most of you that it's not for most people and not even for most people that buy into the idea, the underlying theme behind tiny houses (Minimalism) isn't a bad thing at all.