There's no benefit to replacing the stock lines unless they're split or not replaceable. The reason that people use them is to relocate or run extra components, like oil coolers, or a power steering pump relocation (in which case as many of the hard lines as possible are still retained), or they make the reinstallation of something like a turbo easier (in which case there are usually kits). Braided lines will still fail under the right circumstances (and I've seen pictures of melted ones). TBH unless you were simplifying the circuit somehow there's zero benefit to it, possibly downsides because of the amount of flex braided lines can still have at long lengths.
The braided steel brake lines are fine because they control flex and stop the line bursting out in a system which regularly sees sudden changes, but you're only replacing 1ft sections of it, not replacing hard line and running it along the entire car.
I don't think standard AN style fittings are pressure rated for PS systems, best talk to your local supplier before deciding what to get. The good steel braid style hose is teflon lined instead of just rubber.
I believe the genuine brand fittings will be rated for stuff like this (although kits for oil feed fittings will still give you steel AN fittings because duh), but the hose changes on application like with regular hoses for heat and pressure or fluid. The teflon stuff is typically used where it's really hot, not that you can't use it for anything else.