Auto reply emails aren't a new thing. Most come with a disclosure at the end that it's automated and they have a neutral tone "We acknowledge your reported problem, it's been forwarded to our engineers" (so people don't bother replying back).

I personally would rather get a literal auto reply ack e-mail generated by some python script than an LLM response that just rephrases the context. The python script will be more compute efficient too for this usecase.