For backing up High Sierra (APFS) on a rotating ext firewire hdd, format HFS+ or APFS the ext hdd?

For backing up a bootable MacOS High Sierra (APFS) onto a rotating ext firewire hdd, does formatting the hdd with APFS increase smoother operations? And/or more read/write speed?

I know when being used with Apple M chip computers, APFS is mandatory, but I'm still on an Intel machine.

I'm also aware that APFS is designed for flash drives (SSDs).

Thank you!!