There is no need for acting, a girl would have lots of visitors and make similar amounts of money even if she wasn't cheerful, probably make more if she's the fast-fuck type.

You underestimate how horny some men are. One girl was telling me how it was 15 years ago.. men would line up in front of the apt building, go in, get a blowjob and a quick fuck for like 20min door-to-door, pay 25$ and leave. I don't know if she in particular didn't perform "girlfriend experience" type work or that's how they mostly were but trust me, there are more men who don't care about how happy the girl is and don't give a crap about her being cheerful or not.