Why would you drop a 10GB file in /tmp and leave it there?
Every decent app I've used that processes large files also moves them to a final location when finished, in which case it makes sense not to use /tmp for those, because doing so would turn that final move operation into a copy (unless you happen to have /tmp on the same filesystem as the target location). That's why such applications usually let you configure the directory they use for their large temp files, or else create temp files in the target dir to begin with.
For what it's worth, I changed my /tmp to a tmpfs years ago, even on a 16GB system, for performance and to minimize SSD wear. I think it was only ever restrictive once or twice, and nothing terrible happened; I just had to clear some space or choose a different dir for whatever I was doing.
It's worth reviewing the tmpfs docs to make sure you understand how that memory is actually managed. It's not like a simple RAM disk.