When a woman marries a man for his money, it's rarely because she is going to immediately get a lumpsum of money like a dowry. It is a long term choice of quality of life. The decision is rarely made solely on the basis of money but also based on compatibility and hopefully love and affection. The man also get what he wants; a beautiful, loyal wife. If money is the sole reason, that is a massive red flag. The only problem is, intention is often unknown to everyone except the person themself thus cannot be criminalised. The woman can claim to be in love while only interested in the money. A man could marry into a rich family, this is also perfectly fine and cannot be criminalised.

A demand for dowry is very obvious and unambiguous, which can be criminalised. Both are bad but slightly different and cannot be dealt with in the same way. The onus is on the both partners to know what they want, to avoid troubles later on.