Is shelving in TFS merely a soft checkin so other team members can see the source code?
i.e. the shelved code will not be compiled right?
That's right. If you create a shelf, other people doing a get latest won't see your code.
It puts your code changes onto the server, which is probably better backed up than your work PC.
It enables you to pick up your changes on another machine, should you feel the urge to work from home.
Others can see your shelves (though I think this may be optional) so they can review your code prior to a check-in.