While these are all valid reasons to not pick up the phone much of the time, to never pick it up is a disservice to you and your customer/friend/family member. Discussing things may not be as efficient, but they allow you to reconnect with the real person as if you only use technology they can become a disembodied object in your life, our memories glazing over things like tone and person.
In addition, sometimes not knowing the specific goal of an interaction allows you to sort out problems you never knew existed. Rambling through a call can even lead you to new directions you might never have thought of before speaking to that person.
As for time, not allowing time for a real human connection decreases the quality of those interactions. Sometimes people just want to hear a voice. There a million things transmitted through tone and pauses and subtleties never seen in a printed message.
Calls are necessary. Private time is too. It is a balance that is hard to draw, but too much on either side can ruin a relationship.