I expect that they are the same as the Datasafe T02/TYG02 I get from SVP (and I am thinking that I should not be saying this, and expect that is why I am always the only one doing so) but they have been very good, I have burned 1000's of them, and yes there have been problems with dust, but at about the same rate as I see on the so called premium lines that cost three times as much.
I expect the the answer is...
2. Because they got them ultra cheap and they transfer most of the savings to you.
Have you read the 22 reviews ?
One says that they are TYG03, so not as good as the SVP 8x versions, but I expect that is why they are a few quid less, face it, and most seems to miss this point, what else can you get for the same cost ?