Totally depends on you and what your intentions are, and I guess your mental stability as well. Are you the jealous / paranoid type? Can you mentally handle the fact that your woman does things like bbbj, cim, p2p rubbing, or maybe even bbfs? If your goal is a relationship, and you can't handle the thought of some of these things I've stated, then maybe its not a good idea.
If you're just looking to have fun and know its not gonna be anything serious then go for it. But just remember, shes not your girl, shes everyone's girl.
Also like a couple of members have stated, outside of the spa, these girls are just normal women. So treat them like a normal girl. I took a spa girl and her roommate out to a bar a couple of years back. Another time I took a girl to see Crazy Rich Asians, cause she really wanted to go see it. Most recently I've been meeting with another spa girl, and we've just been going to different parks and walking around. Point is, maybe don't expect sex. Maybe they're willing or want to hang out with you, because they're comfortable with you or they just wanna chill with someone they trust. If you think about it, they get the D multiple times a day, what makes you think she wants it on her off hours? (but then again, that's subjective. depends on the type of woman. if anything let her initiate.)
But yeah... I don't know the status or the type of relationship you have with your provider. So assess the situation yourself, and if you can handle it and want to do it, go for it.