If you've used git+LFS for any extended period of times, you'd know how often it breaks, especially when used with forges like GitHub. Both GitHub and Git treat LFS as an after-thought and second class citizen.
The fact that it's even referred to as git+LFS instead of just git... If I needed to work with large files frequently, I wouldn't want such a basic feature bolted on. Not a criticism of git, just can see why Epic doesn't use git.