What is a jailed shell and should I use one for my hosted site?
If you are using cPanel on a shared platform then you pretty much have no choice i.e. for you to access the server via SSH it will be a jailed shell account you'll be presented with.
This is because you won't actually have access to the OS libraries etc but just the section of the server where your hosting resides so you can run some basic commands etc.
If you were hosting your own server and installed a panel access platform like Plesk or cPanel then you would also have non jailed SSH access as you'd have access to all of the server and its installed components.