The main sticking point for me about the whole narrative with the implied environmental benefits of smaller residences is that most of them (well, mostly the running-through-the-whole movie story of merete and christopher's self-build project) seem to be intended for plopping down in the middle of some gorgeous American West mountainscape... but honestly if you're thinking about reducing the amount of space you take up versus space that Nature gets to keep for Herself, and you also might start thinking about the amount of fossil fuels you burn getting from your space to the space that has your groceries and friends and job, then maybe have you tried this thing we call cities?
I mean, it's not like I'm particularly good at achieving environmental consciousness or living frugally or minimally or whatevs, and I sure don't begrudge wanting to be in the gorgeous American West mountainscape --- it's not really my thing, but my parents grew up in it and are big fans, and that's cool and all --- but I feel like it has to be admitted that driving out all that way parking your tiny house in the middle of it is to some extent an act of consuming (though one might also say: cherishing) that natural beauty, not exclusively an act of preserving or protecting it. Maybe it's still a notch better than parking a giant house there, but it doesn't actually really strike me as very minimalist living such as it is.
I'm being so negative though, jeez. The other side of the story is this really delightful part where it's some people just up and deciding to build things, and looking around on the internet, and thinking "pfff all these other people took 6 months to a couple years or so to build theirs, but I bet I (with exactly 0.000 construction experience) could hack it in 3mo easy" and then of course almost running out of money and taking a year BUT STILL FINISHING. I find that "fuck it I'ma figure this out anyway" really admirable.