Swap files are very fragile if you are using hibernation. For FDE I prefer LVM-over-LUKS and a dedicate partition

In practice, there’s a potentially tremendous impact if you’re using a spinning metal disk. Sectors at the beginning of the disk (which is at the outer edge) are read/written way faster than sectors at the end. File systems tend to prefer writing files at the beginning. If the file system has been used for ‘a long time’ then it’s either fragmented - or it’s been defragmented and the free space is at the slow end of the drive.

One nice thing about swap partitions is that they can be fixed in place even before OS installation.

(Of course, if you’re using swap enough for this to be a huge factor, you probably have bigger problems. But I haven’t done the math.)

Unless you use the Linux package that does manage swap files dynamically.