It’s not a good idea to use regular basil in Thai food. It’s important to use holy basil because it is what gives Thai food its distinctive heat and flavor.
Most Thai dishes don’t use holy basil as ingredient, but in the ones that do, it is an indispensable part of the dish.
Probably the most famous and widespread Thai food with basil is called “pad kapow“. Every Thai restaurant serves the station it is one of the Thai people’s favorite comfort foods.
The holy basil and this dish is indispensable. If you try to use normal basil it just won’t have the same flavor or bite. In fact, it won’t even taste like Thai food.
Some of the local restaurants here in Thailand try to make this dish with Thai hot peppers as a substitute for basil. In my opinion, this just won’t do. It just doesn’t taste nearly as good without the holy basil.
So, I do not recommend making Thai food with regular basil. I know that holy basil can be difficult to find locally, but in my opinion using regular basil in Thai dishes is not a reasonable option.