Unless you’re at the airport several hours in advance, changing terminals at JFK is very inconvenient. I also wouldn’t say lounge access is my “top priority”, but rather, it’s important — and coupled with a shrinking margin between economy on B6 and DL, it comes into play.

I remember years ago a “Airport lounge” sign briefly appeared in T5 (by the 1-7 gates I think?), then disappeared just as suddenly. Now THAT was a tease.