[coldtea]

First of all, that taken literally is just bad advice. You're friends with your friends, you don't ask them on dates. It basically translates to "try to get romantic with one of your friends [of your preferred sex]". Is that supposed to be how people get dates?

So, I take it charitably that you meant "you ask people you know" (not your actual friends/buddies) on dates.

Which is as good as saying "to get a job, just ask for one" to an unemployed person. To which the proper response is "Gee, why didn't I think of that..."

[CocaKoala]

I disagree that it's bad advice - it can certainly be applied badly, but so can anything. You meet somebody, you become friends with them, you start dating them, you get married - that's an extremely natural arc. You shouldn't ask all your friends on dates (just like you shouldn't ask everybody you meet on a date) and you should be cognizant of hints that somebody isn't interested in dating you, but to say that somebody is EITHER a friend OR a romantic partner and there's no overlap between the two is strange to me.

And this isn't the only way to get dates - dating apps certainly try and short-circuit the "be friends" part. But I've been friends with every girl I've dated before we started dating, including the woman I'm now married to. If you're not friends with somebody, even a little bit, why do you want to date them?

edit: And of course, if you're going into friendships with the intention of trying to date the person, that might work out poorly. Meet somebody, be their friend, and if you're both open to something developing, it can happen. Asking them to have lunch is a way to start that.