Well...I have never seen any advantage having anything that relates to a system...hidden from me (sole user).
IMO, system files in Windows are initially hidden (default settings)...because Microsoft doesn't want to have confused users playing with them and sabotaging their own systems. Of course, this also prevents these same users from having a good idea of how to assess problems or repair such when conditions dictate such. Additionally, it hampers a user when trying to assess the growing malware presence on systems. A user who doesn't see or understand how to check the validity of various files and file extensions...is pretty much at the mercy of those who take advantage of such inability.
IMO, hidden system partitions have the same effect, for the same reasons. If you don't know what's there...you cannot repair it, understand its importance or treat it properly.
The assumption that users do not have the "need to know" is patronizing and promotes the concept of the system being a "mysterious, black box" which is incapable of being understood by the user. The result? OEMs sell systems that mandate being returned to the OEM for repairs, upgrades, troubleshooting, etc
Which is why I don't encourage anyone to buy OEM (HP, Toshiba, etc.) systems. I want to know how to do basic repairs, troubleshooting, etc. on my systems. Between the documentation readily available from Microsoft and the zillion websites which provide info...I can do such with confidence on a system where I have installed a Microsoft Genuine O/S in accordance with known procedures. I prefer the opportunity to learn that a computer system is more than a "black box" by experimentation which is supported by a ton of info on what I should do if I go wrong somewhere in my experiments.
The sharing a computer with others is something I've never had to do because I live alone.
But the simple answer to problems that one might face if such resource had to be shared...is overcome in various ways. My answer is to have each person in possession of her/his own system. It's called a "personal computer" for a reason, IMO.
As for encrption and protection against theft/loss...the usual safeguards which have been extolled for eons now. Backups, encryption...or simply failing to have any data on a system...that can make you regret such in the event of loss/theft.
I try to keep life as simple as I believe it to be