Say I am using a hosted site on Bluehost or a2 or another hosting platform which runs cPanel. I'm being required to use a 'jailed shell'. What is a jailed shell and should I use one? I found some documentation on jailed shells here - https://docs.cpanel.net/knowledge-base/accounts/virtfs-jailed-shell/
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.
Using a jailed shell is really a footnote of your hosting provider's setup. "Jails" were a precursur technology to containers... probably not helpful, but it's true. Think of a jail as your own private filesystem. It is a key mechanism to keep users on a multi-tenant system from interfering with each other.
It is good to be aware of where your boundaries lie and if you are using such hosting, it means for hosting CiviCRM, that you may have to request changes to the OS environment. One example would be if you wanted to use wkhtmltopdf for rendering pdf's in CiviCRM.