[ps2000]

Rare use case...

I remember CD burning softwares and torrent clients asking for special temp directories to be used for that.

Allowing every day applications to create GBs of tmp files would mean you would need to worry once your partition has less than 100 GB free.

However, nobody stops you from mounting /tmp anywhere else or even disable tmpfs.

[buster]

Very common for me, not so common for you. ;) And: when is use /tmp on my laptop, it gets cleared after reboot, so that's perfect for _temporary_ files..