LVM makes encrypted swap (and thus encrypted hibernation) way easier.
> Wouldn't it be easier to just not use swap . . . ?
In addition to preferences for hibernation, I'm a firm believer that there's a time and a place for swapping, and that one's system is worse off for lacking that option. I may not push my system's memory limits like I used to, but I certainly have pushed through 16GB, and don't like the idea that there wouldn't be a fallback like ZRAM or swap-space backing up the OOM daemon, which I'd rather didn't kill my processes in all but the most dire of circumstances.
Some amount of swapping will be done by the kernel, even on a 64GB machine with memory to spare, and without the time to do my research tonight, I trust that the kernel delelopers had solid arguments for implementing the behaviors behind that baseline swap usage.
You could make the argument that a swapfile will work just fine, and if you're not going for hibernation that just a few gigs is all you need. Live the flexibility of swap files. I wonder if you could put that behind an encrypted block device within another filesystem, ecryptfs-style.
I've been using a proper swap partition (just a hair larger than RAM, for hibernation) since the late oughts, and, ZRAM aside, am well-and-truely stuck in my ways.