I have strong memories of seeing this teaser trailer playing many times in late 1988 and early 1989 at the Gallagher Theater in the Student Union at the University of Arizona. It was the first time I recall hearing of people paying full admission to a theater just to see the trailer.
(Side note: When I was a kid, we called these previews, not trailers. I know why they're called trailers, as they used to run after the movie back in the old, old days. But why we still call them trailers when previews makes more sense eludes me. I can't even remember when the term trailer came back into fashion.)
I was not yet much of a DC or Batman reader at that time, and therefore only tangentially aware of the controversy around casting Michael Keaton. So this trailer was really the first look anyone had at this movie and it sold it completely and totally.
The importance this movie had at the time for comics is easy to underestimate in this day and age of the Marvel Cinematic Universe. But there was a time in the 1980s when comics fans knew the medium was full of storytelling gold while the general public still thought of comics as kid stuff and the Biff! Pow! Sock! of the Adam West series defined the idea of comic book adaptations. This was going to be the movie that got comics noticed! That proved to the world that they weren't just kid stuff! And then everyone would flock to comics shops to get in on the hobby, making all those collectible issues the die-hards had been hoarding for years worth a literal fortune!
Some of that came true, some of it didn't. But I still think this is one of the best uses of a teaser trailer in modern movie history.