git bronch - branch & checkout in one command

gistfile1.txt

# git bronch - branch & checkout in one command
# > git bronch blah
# Add to .gitconfig or use command: git config alias.bronch = ...
[alias]
    bronch = !"f() { git branch $1 && echo \"Created branch '$1'\" && git checkout $1; }; f"

Ok here's the noob's question: how is this different from git checkout -b ?

Looks like i'm the noob here. I looked at man branch but not man checkout.