Used to have bash aliases, but nowadays I work on so many different machine, without my dotfiles present, that aliases seem kinda pointless. I'm a fast typist.
I would wager that above 90% (of those using command-line git) do, after at most a few weeks of heavy git usage
It takes no time to add some, and it's not necessary to put them online and synchronize them; it would be a no-brainer for me to add some manually, if I had to work on a new machine for more than a few minutes (and couldn't access my usual ones from it)
They're shorter and let you be more efficient at common tasks.
They also tend to be personal and hard to share. Which can make it harder to explain what you’re doing to a coworker for pairing/debugging/training purposes. And you have to remember both the aliases and the underlying commands/options, at least enough to remember when you don’t want to use the alias.
I don’t find that I use git subcommands with a frequency that makes me want to alias them. It’s likely that different workflows lead to different optimizations.
I was always using 'co' for checkout. Made the change to switch ('git s') and revert ('git r') and it has been pretty seemless. I do wish 'git reset' defaulted to --keep.