Actually, they do use some of the same praise songs--translated into Chinese.
But they also have some wonderful ones of their own as well as from Taiwan and Singapore.
The problem with translating Euro-language songs into a tonal language (Thai, Vietnamese, Cantonese, Mandarin, etc.) is that the tunes must follow the tones of the words or one is singing nonsense syllables.Translations that maintain the tunes are generally verbal nonsense or are changed to unrecognizability.
You can't simply change the word order to make the tones fit the tune because word order is more important than it is in English. If you change the word order you change the meanings of the individual words because the tonal languages tend to be highly conceptual- meanings depend a lot on immediate and more general context.
I have heard Amazing Grace rendered in Vietnamese. It is still beautiful but it isn't the same song at all. The words translated into Vietnamese cannot be made to fit the tune so a different set of words must be used that sort of connects with the song in English a little bit.