Your comments

Please don't integrate `git lfs clone`. Steve Streeting and I added this workaround a while back but it is deprecated now: 
https://github.com/git-lfs/git-lfs/pull/988
https://github.com/git-lfs/git-lfs/pull/2526

In Git 2.15 I added a new way to smudge files in parallel. This makes the default `git clone` command as fast (and sometimes faster) than `git lfs clone`. This is supported by Git LFS 2.3+
https://github.com/git-lfs/git-lfs/issues/2466

tl;dr:
Make sure you run at least Git 2.15 and Git LFS 2.3. Then use the standard Git commands for best performance :-)

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Please add an option to the custom "Diff Tools" to enable the smudge filter for the diff'ed files. That would be necessary if you want to compare the content of the Git LFS object (e.g. image files). This explanation is very brief. Please ping me for more details: https://twitter.com/kit3bus