It's seemed to me that all the uses of .io so far are precisely for sites only developers will have any reason to visit--software libraries, B2B SaaS, etc.
Railing against re-use of small countries TLDs is the 2013 version of writing "Micro$oft".
I remember reading about how Japanese advertizers would use Google queries in ads instead of URLs - and we in the West did little to improve on that with QR codes - so it's possible that there's a place for .io somewhere. I just think it'd be a really bad idea to use them interchangeably with .com domains.
I guess the same can be said of .co domains, which look like typos to the average person, when they aren't used as shorturls.
That's happened in the UK as well, though (in my experience) more often with video adverts (e.g. movie trailers) than print advertising. It began with stuff like "AOL Keyword: harry potter" (was it "keyword"? can't remember, was definitely AOL), and mostly died after that, but have seen it with Google a few times.
And on the flip side, you seem to suggest that QR codes are a western thing - actually they were invented in Japan, and are much bigger in Asia than over here.
This is probably because it's hard for the Japanese to correctly remember web addresses, since they're in the Latin alphabet. By having them remember search queries instead, this problem can be easily avoided.
Many users just type website names into google or their location bar, not paying any attention to the URL at all. Or, actually type the _hostname_ into a google search box, not realizing what a hostname/URL _is for_.