I run Devuan on an old 1GB ram laptop, & I give it 2GB of swap, it works well enough as a basic machine, it even goes online with Firefox, if a little slowly, but perfectly usable. Two other old laptops with just 2GB ram, I don't even bother with swap.

If you have a laptop, & want it to hibernate, you will want a swap partition of equal size to your ram.

Is there any performance difference between partition-swap and file-swap?

On an SSD, probably not, assuming you're using a non-exotic filesystem. On a mechanical HDD, the traditional reasons for using a swap partition are avoiding fragmentation (and thus expensive head seeks) and the ability to place the swap partition on the fastest part of the disk (pi and RPM vs linear velocity and all that).

It certainly was, and he sure does.
My (admittedly fairly limited) real-world tests don't show any performance penalty for swap files though, at least not on an ext4 formatted SSD. Swap files have been a thing for many years, so I'd expect most of the bees are ironed out by now.

TBF, BTRFS is a COW filesystem. Swap files on COW filesystems are always going to need explicit support from the FS, and are always going to be a hack.
If running BTRFS (or ZFS), I'd go with a swap partition any day. Ideally more than one and on different devices so they can stripe.

@p.H over at the Debian forums maintains that swap files are a dirty hack because swap is designed to operate on block devices and they seem to know what they're talking about (and certainly more so than me). The fact that btrfs has only recently gained the ability to support swap files would seem to confirm this.

P.S. In my first draft of the above, I wrote "duel-boot" instead of "dual-boot," which is probably more accurate. :-)