Do people really care much about how beautiful a human made poster look like? I don’t think I’ve ever seen that as an issue, a poster doesn’t have to look fancy. Though if I love any art piece then learn later it was made by AI I will for sure update my judgement and dismiss it as if I was tricked in the first place. You’re way better using Word art for your poster than delegating to an AI if you don’t want to receive negative attention