Yes actually I did once -- at a halal place (I believe at Pei Ho), it was good/tasty.

My observation was mostly the feeling that at a restaurant-style hawker centre, you feel some obligation to order some certain amount or inability to just try a small dish because of the setup (feeling like a cover charge) when you sit down in their "territory". (and I did note that the feeling of "territory" seems stronger at these HK centres than in Singapore). Versus stall-style (Singapore), you're free to order as little as you like and have no obligations. Maybe this is just my bias, and they actually don't care either way.