Yup. The Thai English teachers focus on grammar, while the native speaker is allowed to put the language in action, with conversational exercises, speaking activities, Q&A, etc. Dept heads especially love photo ops where the students are taking turns giving recitals, as the farang guides them along. Look, they're speaking English.
The rationale is that the Thai teacher's limited English is sufficient to teach them grammatical rules, while the assets of native speakers can best be used to actually demonstrate the language, so that students can hear it spoken with correct (or closer to it) pronunciation, which they're unlikely to get anywhere else in their daily lives in Thailand, especially out here in the countryside.
I don't mind at all as I hate teaching grammar, and my MA in English actually took pains to tell us not to teach it explicitly. Don't teach the rules, show them. Give them language they can immediately put to use. They can't ask for help at the grocery store with a table of past perfect and past continuous conjugations. That's what Chinese and Japanese students typically get, which is why they now come to me online, telling me that after their years of English in high school and university, they can barely speak it.