I mean I theoretically don’t mind the idea of myself as some cocktail swigging bed hopping glamazon but outside of Sex and the City that kind of dynamic doesn’t really seem to be that productive.
But what you're describing sounds more like casual sex than an FWB arrangement. I see the latter as a compromise - if you don't want a committed relationship but also don't want the hassle of casual dating, with all its risks and frustrations, especially for women, then having a 'sex buddy' can be a good set-up. You can have regular sex with someone you trust and like without having to commit to them. Of course, this can often be better in theory than in practice, but the same is true for all sorts of relationship formats.
Maybe it’s different if one has a social demographic where one meets a lot of normal guys and see what arises “spontaneously” but I think often the guys who are going out of their way to “get casual sex” are a bit odd or unbalanced.
But like I said, the FYB set-up means you avoid the risk-taking that comes with casual sex and instead have a sexual relationship where you both trust and like each other. Are there risks of meeting someone 'odd or unbalanced'? Sure. But as Gabilan so rightly said, one glance at the 'Relationships' page will show you that therea are plenty of 'odd or unbalanced' - and much worse - men in more conventional relationships too.