For me it is both - yes, entertainment and companionship, but this hobby has also dramatically improved my life in a specific way.
I used to hook up with girls and date them primarily for access to sex. I'm a very attractive guy, tall, "Chad" type, money isn't much of an issue, it's fairly easy for me to get laid if I want to. More often than not that comes with a whole lot of drama attached though, especially if you don't really care much about the girl(s) as a person. It's also a huge time sink.
I find occasionally seeing escorts and focusing on my personal life, career, building my own business, other hobbies - instead of chasing pussy - is a much better and more efficient way to spend my time. Ultimately I am a lot happier, because everything I do is for myself, and not to please someone.
This doesn't mean I am not dating at all, I do sometimes. But I'm extremely selective, I really have to like the girl, be genuinely interested in her, care about what her story is, like to have conversations with her. If I find someone like that, which is extremely rare but does happen sometimes, then I will only have sex exclusively with that girl. I also find that I am now a lot more relaxed and happy in a relationship, no matter if it's casual or more serious, because I will be spending time with someone I genuinely like and know that I can always go back to being happy by myself if things don't work out.