I mean, we're a capitalistic culture, are we not? I think it's fair to suggest that monetary value is at least more directly quantifiable and, in the American culture, one would have to have an eye towards eventually monetizing something for it to constitute a scam.
Again, I can't walk into my local coffee shop and get an espresso on my word. "Hey, I'm a relatively unknown gambling writer who most consider a generally nice guy as long as we keep the subject off of religion. How about an espresso, please?"
Beyond that, maybe it just has something to do with the fact that I don't place a ton of value on these non-material things that you suggest people scam for. I don't place a lot of value on money, either, but unlike the non-material things, I do need more than zero money to buy other material things (such as food) that I do need, as well as what few things there are that I actually merely want.