When our helper started, I used to bring her out for lunches / dinners, to be nice. Then I realized it only made her uncomfortable, especially if I was with friends and she was the only helper there. She's a lovely person - and doesn't mind going to big Chinese casual family dinners if the baby needs looking after - but she's not particularly interested in sitting in some restaurant that costs HK 200+ per head. She would only order the cheapest food and would find excuses to go walk around with the kid.
She's really comfortable at home with us, and appreciates being part of home-cooked meals and celebrations. But, if she had a choice, I think she'd rather have an evening off with her Filipina friends than sitting in a restaurant with us if she didn't need her around. She'd probably rather have an occasional HK $50 fast-food gift certificate or some extra grocery money to share with her friends than a HK $200 meal.
Every helper is different. Why don't you just ask her?