Phone sex for fun = good. Phone sex for money = meh.
I spent 2 years as a phone sex provider, including 3 months with it as my only source of income. The money was great. I was constantly surprised how much money people put into phone sex. But, of course, when you get paid, it's about the customer and what they want. Actually enjoying it yourself is rarely part of the gig.
In fact, while I am normally all for phone sex or general over-the-phone foreplay, when I was doing it for cash, I lost my taste for it almost entirely (temporarily).
It wasn't ALL bad. Every once in awhile, you would get someone who was smart, funny, charming and a pleasure to talk to, who mostly wanted to talk. Of course, there was also the guy who got off from the sound of sneezing, the guy who had a balloon popping fetish, the guy who dreamed of me flying to NYC to perform a circumcision on him and the guy who fantasized about his 65 year old wife having sex with 20 year old men.
I know it's almost cliche, but so many of them were really looking to cure loneliness or just have someone not mock them for whatever odd thing they might be into.