I wonder when we'll start seeing these gaining traction 
Something to be aware of...
I read that article as well. Its an interesting read but I'm not concerned. If you believe in "think before you click" you are going to hover on a link and check it no matter what the file extension / TLD is.
I suspect the most common usage of these domains will be for malicious reasons. There's an interesting approach detailed here. I'm also wary of application behaviour changing such that filenames become clickable domain links. For example double-clicking a filename to select all the text of it could result instead in a domain opening in a browser.
If I start noticing things like that then the TLDs will be going in a blacklist in trusty Pi-hole. It'll be be interesting to see if they find their way onto Spamhaus's most abused TLDs live list now that they're generally available.
As you suggest, good practice and common sense are always needed.