Dating at the age of 20 something while still in school is different than dating as a 30 something year old single mother so you'd better believe the criteria is different.
I wouldn't expect most 20 something year old guys to have much to offer in the way of money as most (unless they are very fortunate to be trust fund assholes) are starting out in life. So there a young girl would have to consider his upbringing (as far as how he behaves) and his earning potential (how smart he is).
When I dated whether I was younger or older the man ALWAYS paid. If there was a question about it, there was no date. He could always decline a date with me if he found me to be not pretty/smart/interesting enough in kind.
I dont see what the big mystery is. We all have our own criteria for who it is that we choose to spend our time with.
If a woman chooses to pay for a guy, that is on her but then I dont want to hear her bitch and moan if the guy turns out to be a user and dead beat down the road because not only is she sharing her whole self with him but she gets stuck footing the bill too. <---- THAT IS ON HER.
I would NEVER go out with a man who would question who pays as we would not get along - period. Simple.... shmimple. Why should I waste my time or have him waste his?