I also think the model of delaying sex is overrated; I just wanted to describe how to do it, for someone who wants to do things that way. People vary in sociosexuality, so some people perhaps do need to delay sex due to the way that they are wired.

Yet I think the "wait for sex" cultural discourse may often go beyond people's emotional needs, and encourage even more delay of sex, even for people who would otherwise want to. This discourse contains certain toxic notions, such as slut-shaming (e.g. women being devalued for being "easy"), and "why buy the cow if you can get the milk for free" (because the cow has more to offer than just "one thing," duh).

A strategy of having sex within the first few dates, while also trying to get to know the person and connect with them, is probably most efficient, if you can comfortably have sex with that person during that timeframe while being willing to risk that a long-term relationship might not work.

As you note, sex is an important screening tool. It also can be useful for getting the sex out of the way. Then whoever is expected to initiate it (usually the guy) doesn't have the mental overhead of wondering if/when it will happen, and if any of his behaviors are making it more/less likely. Sometimes, a guy will be acting differently after sex than before, and the only want to find out is to have sex with him.

Also, having sex means that no mental resources are spent delaying sex, and that date venues aren't so restricted (for instance, my previous comment would advise against watching a DVD alone with someone you are dating if you want to delay sex, because that practice is often used to advance sex).

Once people stop doing a complex and cognitively-costly dance around delaying sex, then it's a lot easier for them to focus on each other.