Since it's right up front in the headline that it's Burger King,I don't think the fast food part is “undersaid”.
> I just don't see the point, vs a high-protein high-fat patty made of bean or soy protein isolate that tastes good in it own non-fake-fast-good-meat-burger way.
If you don't see the point of fast food, you can, I hope, at least see that lots of people do.
And since there are people going off meat for environmental or ethical reasons, providing them an open which is both attractive in taste to their current palette and fitting with their existing lifestyle but for the change they are deliberately making seems to have obvious value.
And it can't be cheaper than a real meat burger, because consumers will kill its adoption by calling it the "cheap" product. Regardless of merit or quality.
(Source: the recent book Clean Meat.)