The term "financial interest" is indeed somewhat ambigious, but promoting sex services (and / or prostitution) is out of the question.

It means that these women are unwilling to carry any of the expenses involved: meeting(s), travelling, hotels, restaurants... you can easily come up with a decent bill for any or all of them.

In other words: some people (yes, mostly women) look for "financial stability", i.e. a rich partner (man).

Whether that is "good or bad" or "morally correct" is a different matter altogether.

There are people who like money, wealth and material. They exist. That is all.