If I created a swap partition in LVM I can force it and move it around to the best location WRT multiple hard drives and possible mix of HDD and SSD. With a file its a little more abstract and I could emulate it with some pointless abstraction, but why bother. A typical "this century" example would be running my boot and swap on local disk and storing all real world data on the NAS over iSCSI. Obviously now that "Everything" is virtualized this kind of system administration is void unless you're admin on the cluster itself LOL.
The problem with swap is memory seems to have gotten cheaper than storage and swap of any form takes storage space. Its not the capex that's the problem, its the opex of now you've got an extra 32GB that "has to" be backed up and "has to" be virus scanned or whatever security theatre, and that swap file "has to" be treated as the highest security PII HIPPA PCI category because who knows whats been swapped out of memory onto it, it could be chock full of CC numbers how do you know for sure unless its empty or not there? Paying for more memory doesn't increase your backup storage / security risk / virus scan times and the latter costs more than the former. I don't think non-cloudy admins realize there are cloudy admins out there with forests of little systems with like 8 GB of ram and 16 GB of storage, so the "old" rules from the 1980s about provision twice your ram as swap would increase the disk required from 16 GB to 32 GB doubling my costs for, essentially, nothing. Another problem with swap is in the old days if you needed more memory than you have physically you had to buy more memory, then for awhile you could emulate memory very slowly with disk but much faster than calling an IBM CE and buying more memory, now if you need more memory you spin up more instances or rebuild the instance on a larger flavor about as fast as how you'd add swap in the olden days, probably faster and it can be done dynamically in some architectures.