This is a somewhat complicated question in that, especially in Thailand, there's a moral component to alcohol consumption that will be included in how it's viewed by your gym. Trainers who drink aren't viewed as super dependable by those who don't, students who drink are socially engaging with those trainers, but will also be dismissed in some ways by those in the gym who don't. If you're showing up and working hard, you'll be appreciated for that. If you're tired and drained - even if it's occasional - and it's known that the reason behind it is that you were out drinking, you'll be judged for that in addition to what you'd be chastised for if you were just having a "bad" day.
I'm in the same school as Madeline, where I just can't afford feeling shittier than I would if it were simply a rough night of sleep or being tired from the work I'm already doing. So, I abstain for the same reasons I don't eat sugar or stay up too late to watch Netflix or whatever else. If it's compromising my training, it goes. But people have different goals and different motivations. The 5AM runs make me a total asshole for the day and I still go do those, so we all make compromises, hahaha.