I kind of think this idea is cute. Basically, it's sewing a bottom onto a bra to create a dress. Now, personally, at my cup size and overall size, that's more flesh than i'm willing to show. But I do think the idea is really cute for people who are a little more in-shape (and to whom the phrase 'my cup runneth over' does not have dual meaning)
Plus there are some really cute bras out there that cover more flesh than your average bikini top.
I think personally I'd take the idea and run with it in the sense of, using my bra as a base and basically completely using the pattern except sewing a bodice over top of the bra. I know that seems like there's no point to using the bra at all then, but the thing is, the bra would go perfectly with the dress then, plus I have two new bras that I bought without trying on that fit kind of wonky but would work perfectly to use for something like this.
Regardless, the DIYStyle girls have some really cute ideas, definitely worth checking out.