Basil is in many, many Thai dishes but that is not why there is basil in so many of True Thai's entrees.
My mom grew her own basil in our garden and she put it in almost everything which is why True Thai uses basil in so many of our our entrees. It's kind of funny but the more I think about it the more I realize that True Thai is really just Anna's Mom's Thai!
Basil is excellent in stir fry dishes because it imparts a wonderfully intense flavor to everything you pair it with. That's what a chef would say, but a cook like my mom would just say that basil is good for you. A lab researcher (which is what I used to be a long time ago) would tell you basil is good for you because it is an excellent source of Vitamin K, as well as being rich in iron, calcium, Vitamins A and C, potassium, manganese and magnesium.
There are four nations that make heavy use of basil in their cooking: Italy, Laos, Vietnam and Thailand. Needless to say I like Italian, Lao and Vietnamese cuisine a lot!