Here's the issue with the notion of "interpretation" and that is the fact that they even left it up for interpretation to begin with. Although technically they are correct that this is indeed a DS/DSi cart flashed with NTRBoot, they at no point made it clear that it can't play DS games. They even have "FAQ" section (a stolen one) and it doesn't include this information. This means it's either up to the user to find out this information on their own or ask them directly for this answer.
This is only made worse when you consider the cost of the cart. It cost more than the their other cart, which to an enduser makes it appear as though it has to do more that just install NTRBoot. They are basically banking on vaguely worded statements and lack of information in order to sell this cart. If they actually flat said in the FAQ, "It doesn't play DS games," then no one would buy it nor would we have seen the spam created because of them. Why? Because no one wants a uni-tasking cart when the R4i Gold only costs like 1$ more and plays DS games.
I would also like to make this clear that I wasn't the only person who thought it played DS games. In fact a lot of the spam we got included playing DS games, which means their vaguely worded sentence worked. I just happen to be the second person pushing this fact because I think it's wrong to mislead the community like this. They are charging more for a single task cart, while giving the illusion that it's something more. If the cart was like 10$ (max) and was upfront in the FAQ, it wouldn't be so horrible, but instead it cost more only to do less.