I think the "main problem" with them is that they use a connector commonly used for AC medium and high voltage supplies, and make it way too easy for accidental connection directly to the wall....
In this case, at least they've used the other gender of the connector, whcih isnt commonly used on cords...but there have been some computer power supplies and other devices that include taht connector for plugging the monitor directly into (msotly old monochrome AT-style systems), and of course at some point someone thought it was a good idea to make a wall cord that plugs into that socket, for whatever reason.
I run into those cords periodically when I pick up boxes/bags of cords and adapters from various places/people, so they're still out there, and I can imagine people who don't know anything about such stuff having "lost" teh cord that really plugs into it to charge it, digging out one of those old cords andplugging it in just to try it out.
Thankfully they're not common, but they are out there.
But the basic issue is using a connector that has "always" been commonly used for AC, for a DC connection....
