They work a bit differently, udevil is more like a mount helper. It's used in LibreELEC by udev when block devices are connected. You can point it to a block device, an iso file or a network share and it will create mount point and do the mounting for you.
AutoFS on the other hand runs as a daemon and mounts on demand. It mounts an underlying filesystem on the mount point that detects what you're trying to access, then mounts it and unmounts after a set timeout. Very useful for network mounts that can be problematic if they become unavailable for whatever reason. When properly set up, it makes NFS/CIFS mounts feel like they are local.
There's only one problem, AutoFS isn't part of LE. Not sure they would want it either as Kodi handles network mounts through libraries and it works fairly well. There's a bit of good news though, as I like having AutoFS available I've packaged it up in my fork. Perhaps you or someone else who takes an interest in it would look at making it an addon (shouldn't be much trouble) and upstreaming it. It compiles and runs great both on arm and x86.