-b in checkout is short for "branch" while -c in switch is short for "create".
IMO the UI of git switch is much more intuitive, since the argument is always a branch and the default behavior is to switch to an existing branch. For slightly different behavior (like creating the branch first) there are flags.
So I think it's good that the flag for switch is a different one than for checkout, since the interface of git checkout was quite unintuitive IMO.
The complaint has been, for ages, that checkout got that wrong. As designers, these developers are improving: They got it more right on the second try.