> Sorry for the uninformed question
Don't be! It's good to think about security :-).
But keep in mind that "the most aggressive attacker" is a bit of a poor threat model. It sounds like a shortcut for not having to think about it, and therefore it misses the point.
For instance:
- Could it be the case that someone points a gun to your head and asks you to give access to your OS? Probably not => that's a first step in defining your threat model, where you can assume that nobody will force you to give up your password.
- Will someone have physical access to your computer? If you have a laptop that you carry around, it may get lost/stolen and therefore you probably want encryption at rest (i.e. full disk encryption). Even if it is your desktop computer at home, one could imagine that it gets stolen. If it is a desktop computer at work, then employees may have access to it. If not encrypted, they could just read what's on the disk. Or they could plug a keylogger and read everything that you type on your keyboard, etc.
- Will your OS be exposed to the Internet? Will it expose ports or can it be completely hidden behind a firewall?
- Are you the only user, or is it possible that another user gets phished?
- etc.
Those are all questions (but it is not an exhaustive list) you need to ask to decide what is an acceptable security model. If all you do is browse the web, maybe you don't need QubesOS (because you don't have anything to compartmentalize). If you sometimes need to write an email anonymously, again maybe you don't need QubesOS but you could go with TailsOS. Depending on the threat model, maybe you will want a brand new computer just for the "sensitive" activity you have, and maybe you will only connect to the Internet from "outside" (i.e. not your personal WiFi). Etc.