Where do most of these formal phrases and questions apply?
Basically, from my personal experience in my years in Indonesia, I realise that most of the phrases and questions are boiled down to much simpler/ informal slang. Most people I communicate with understand and also use the simplified version of Bahasa. So where would I have the need for formal Bahasa? Many times I'll refer to my Indonesian friends to confirm that certain phrase is applicable and most of times they say "no one even says that."
The most likely is when someone is talking as their profession to a client, strangers, or in TV and such.
Take the word "Anda" for example which is formal version of "you", it's almost never used outside of that situation, co-workers usually call each other by name or "kamu", employee refers their superior as "pak" or "bu" which correspond to "sir" and "mam".