I lived across from an elementary school in San Jose for 7 years and I loved it. No house/cluttered garage across the street to look at and no cars on the streets in the evenings or weekends. Worked out like having a private park with play ground etc. Morning traffic was a little tight, but I went into work late, after drop offs were done, so it wasn’t an issue for me.
I would have been much more hesitant with a HS though. More chance for vandalism, noise, dances etc. Most of my friends would say “it’d be great to live across from an elementary school, wouldn’t live near a high school though” for whatever that’s worth. I’d guess resale will be lower if you are in the walking path of high school kids. Just my 2 cents.