Camber shims and the like are not exactly new technology, nor particularly fancy. Furthermore Red Bull have liked working with aggressive camber settings before (and good on them for it). If something happens during the race, be it a short stint or a different tread compound and you feel like you can get away with running more aggressive camber - why not?
Don't necessarily think it has anything to do with whether or not there are "aero tricks" yet to be found. You have parallel development all over the car - and if this is a tool to make them more competitive during a race... why wouldn't you do it?
Grip is a four letter word.
2 is the new #1.