Ideally.
Not as a requirement.
For most people who just want to post about their cats on SAFEbook, running a vault while their computer is on should be enough to do everything they need/want to do on the SAFE network.
The DNS system is a moot point because anyone can implement any system they want. Somebody will forgo traditional DNS for petnames and others will want the more traditional DNS system. There will most likely be an app that simplifies registering to most known DNS systems at the click of a button.
What people are discussing when they say they should have a LiveCD-based SAFE operating system and redundant two factor authentication is a situation where you have something major to lose by a loss of privacy and/or anonymity and/or unauthorized access to your files. Such as a whistle-blower or a political activist and the like.
You don’t seem to get that just because a system or feature is suggested, it does not mean everyone needs to adopt it.
I think I speak for (almost) everyone when I say that when people discuss these things, they aren’t saying “Yeah, I think we should definitely impose this mode of doing things on just about everyone.” but rather they’re exploring the possibility space and seeing which ideas are plausible and where the weaknesses and strengths lie in each proposed way of doing things.