The question is then, do the benefits to your friend, and others like her, of not criminalising the buying of sex, outweigh the very significant costs/damage of prostitution overall?
I'd say no. The very wide ranging harms it causes to society, and to many coerced/trafficked/vulnerable individuals, and to the perceived status of women & girls, are much more important than pandering to a tiny number of 'happy hookers'.
We, for example, ban smoking in public places, selling/possessing cocaine, and driving without a seatbelt. All of which are very frustrating to some people in the UK. Tough. It's the law.
And it should also be the law that renting someone else's body to use and abuse for sex is an illegal act.
Criminalising the buying of sex is only the beginning, of course. For example, there'll need to be increased support and exit routes for prostitutes to escape. Plus additional funding for specialised police officers, ideally females will be key. The Unbuyable Bill was not a perfect policy intervention, but it'd be a great start, to then build on.
Criminalisation makes a very clear statement to men and boys that sexual consent cannot be bought. Consent must be made enthusiastically and freely, else it's an unwanted abusive assault. A true 'yes' never ever needs money.
And it tells women and girls, that no, men cannot rent your bodies by the hour. You are deserving of respect and dignity.
Your 'happy hooker' friend could probably hide well under the police radar. Difficult to prosecute if she's going on all those lovely 'dates' first. And as she's not got a long history of A&E visits/broken bones/STDs, homelessness, substance addiction, growing up in care or abused as a child, it'll be tough to build a robust case against her unusually small number of punters.
I do wonder what the ratio is between her 'happy hooker' and the much more common horror/terror stories?
Very, very few men have hundreds of pounds to cover a nice outing and a £300 fee on a regular basis. So probably 1 in a 100 or fewer? That's clearly unacceptable to anyone bar a sociopath.
So ban the buying of sex.