Fedora uses tmpfs for /tmp. I think it still makes a lot of sense to use tmpfs for a heavily written-to transient file system.
Arch uses tmpfs for /tmp.
Arch has you set up your own fstab so pushes the choice to the user?
During installation the guide tells you to run a program, which generates an fstab based on current mounts. So by default it will configure /tmp the same way it’s configured in the live cd.
Actually the installation guide for arch asks you to use `genfstab -U /mnt >> /mnt/etc/fstab` which basically copies over whatever was mounted at the live environment (taking off the /mnt), I'm pretty sure tmpfs for /tmp was there by default last time I installed.
I ran out of space on NixOS with tmpfs, they run all builds in /tmp so my swap ran out.