Looking at the docs I'm not sure what functionality that adds over git. It seems like just a GUI, no extra abstractions for the complicated operations. E.g. modifying older commits[1] still looks to require manually branching, resetting, making the modification, rebasing/cherry-picking from the previous branch, fixing any conflicts, and then deleting the previous branch. That's pretty shitty for a wrapper, it should just be "right click the commit, click modify, make edits, resolve any conflicts". The porcelain shouldn't expose the plumbing so much!

[1] https://docs.syntevo.com/SmartGit/Latest/HowTos/Modifying-th...