How is a phone call not the highest form of immediacy? Short of an actual pager event implying downtime and process, what could be higher priority to someone working out of office?
A voicemail. I frequently get calls, some of it may be a high priority, some of it not, no way to know, but I am not going to answer every call. If someone goes through the effort of leaving a voicemail I will interrupt my work and listen to it and decide whether or not it is more important than what I am currently doing.
I think it really depends on related context though. If I am working in an operational capacity then I may need to answer the phone every time it rings. If I am doing project work requiring a great degree of creative problem solving I am going to block off my calendar most of the day and prioritize a lack of distraction. My phone will be on "do not disturb" and I won't be looking at it. Impatience and interruption are the killers of creativity.
If you treat every inbound phone call as your highest/immediate priority, you have ceded all control of your priorities to other people. Unless you’re working in a call-center type of role, I can’t see how that could possibly be optimal.
