Despite my overall disliking for cPanel/WHM, one feature that it has that comes in very handy is the Jailshell. Hosting clients, when granted shell access, should not be able to see anything except for their domain, their files, and their folders. They should feel like they are the only ones on the system.
I believe that jailshell also keeps people from even attempting anything malicious or overstepping their bounds, simply because they can't even try to open files that they shouldn't, because they are invisible to them.
The Virtualmin vs. cPanel comparison as a selling point should not ignore the lack of this feature. Jailshell is an important tool for web hosts because of the growing number of customers who request shell access with no intention of harming the system or gaining access to other users' files.