- Facebook does not use Git due to scale issues with their large monorepo, instead opting for Mercurial.
- Mercurial may be a better option for large monorepos, but Git has made improvements to support them better.
- Despite some drawbacks, Git usage remains dominant with 93.87% share, due to familiarity, additional tools, and industry trends.
I thought it was exactly the same based on the description.
No the old commit is always there, marked as obsolete with the information of what it became. No holes in history. (Assuming you use the obsolecense markers)