The demanding tone of the questions is because I don't want the OP (nor any other readers, for that matter) to get the impression that the import models are a care-free alternative for high-end features.
1.1.) If there is indeed a local retailer (and by this I would make a clear distinction between a retailer and a seller), which is providing the warranty and repair service, then they should be a fairly safe option.
1.2.-1.3.) I wouldn't put too much trust in credit card safety:
https://www.theguardian.com/money/2...ace-purchases-not-covered-consumer-credit-act
http://www.moneysavingexpert.com/credit-cards/PayPal-Section75
But yes, on most cases the credit card will work as a safety net in the case of a total failure of the product, at least inside the first 6 month period. But from what I've understood, with credit card refunds you're usually first required to try to settle the matter through the retailer (or the credit card issuer will do it for you). If the seller/retailer wants to get difficult, after 6 months they can require the buyer to prove that the fault was because of a manufacturing flaw, and not a user error. Bigger companies won't resort to this, because a good brand image is worth more than a random individual refund.
Also, I don't think the credit card helps if the flaw isn't even covered in the warranty. For example in the case of backlight bleed and dead pixels, if the seller/retailer clearly states that they are not covered (which happens quite often with the import models), then it's not considered faulty. If the retailer/seller can prove that they've held their end of the bargain, you might not get any refunds. The credit card is a useful tool, but it isn't the "ultimate answer" to everything.
2) He wasn't filming it from the beginning. When the video starts, it's already smoking. In the video description he said that it had been smoking for over 30 seconds before he managed to plug it off the wall and started filming it. And yes, it was tested. It was working ok even AFTER it was mounted on the arm:
... I started filming after 30-45 seconds of it smoking, and this video is around 30 seconds long, so it was super heavy at the start and smoked for over a minute...
...
The monitor hadn't been physically moved for 4-5 weeks and was operating completely fine on the monitor arm that it's mounted on in the video. I mounted it, plugged it in, and worked on it completely fine for the first 4-5 weeks. Then all the sudden it just blew up.
(previously I said several months, but it seems it was weeks, after all - which actually makes sense, as he was also talking about restocking fee, which usually only works for the first 1-3 months, I think)
Not sure to what extent it was a user error in your NEC case, but it might also still have been a design flaw. There should be some tolerance with the screw lengths, meaning if they state 10-15mm, then a 16-17mm screw shouldn't pose a threat, yet.
3) Just because someone sells a lawnmower as a TV, doesn't make it a TV.

Furthermore, try as I might, I still can't find anything but speculation discussion, if I search the web for "freesync tv". Not sure if there is something on the Korean/Chinese sites, as I can't read or write either.
But technically speaking, if there is no tuner in it, then it simply isn't a TV.