In brief
git switch -c feature creates and selects a new branch. Plain git switch feature normally selects an existing branch.
Useful to know
git switch -c feature creates and selects a new branch. Plain git switch feature normally selects an existing branch. [1]
Switching is not a backup of uncommitted changes. Git can refuse an operation that would lose them, but inspect status first. A separate parallel checkout is a different tool from switching branches over the same working files.
Sources
For further detail and to check the information: