Are you 100% sure that there is nothing you are exposing via your git repo that you want to keep away from the person who manages to hack your server or discover some means to reach the repo externally?
Getting hacked is not inevitable, but if you treat your systems as if it were you'll be a lot safer if it does ever occur.
If you push via git or via rsync, you're typically going over SSH in both cases. As far as the .git directory, my post-receive hook also does a "cp -R" of the files to the actual web-served directory (there's a build step in between anyway), so there's no .git exposed. As far as security, as long as one knows to handle the .git directory, there's no difference.
Are you 100% sure that there is nothing you are exposing via your git repo that you want to keep away from the person who manages to hack your server or discover some means to reach the repo externally?
Getting hacked is not inevitable, but if you treat your systems as if it were you'll be a lot safer if it does ever occur.