I get the desire for narrative and different colors...but this looks awfully simple-minded. Why can a boy age 5-9 play with erector sets and legos, but a "girl's" engineering toy must comprise such a primitive set of components?
Anyway, parents know what their kids want more than anyone else, so I think the option of gendered construction toys is great (so long as the market doesn't become dominated by them).
"Erector Sets" sold in the us are actually rebranded "Meccano". I'm not sure when that change happened, but it seems like that is what I actually had. I guess they bought the brand for marketing reasons.
Personal anecdote: when I was a girl I wanted this $50 erector set for Christmas which my dad said was too expensive, but then he bought me a some $50 stuffed animal for Christmas anyways. I guess he felt like it was a better gift.
I haven't heard how the new "Lego Friends" line has been doing, though.