Personally speaking, as a person who often works from home, my favourite form of 'workplace' communication is the telephone. The reasons for this are various. Here are a few of them.
It doesn't matter what you look like
...or whether you've bothered to get dressed. Whether you're wearing your trackies, you've got your breakfast down your T shirt or baby sick down your back, no one knows! Sounding professional is much easier than looking professional.
It's easier to make yourself clear
On email and other written communications people can sometimes be misunderstood. Their tone can be misinterpreted, or people simply don't properly read what has been written. On a phone call you can get instant clarification that your opinions, instructions or ideas have been comprehended and properly digested.
It's quick
It takes much longer to type out a sentence than to say it, so using the phone as your favourite workplace communication tool is a time saver.
It's personal
Unlike email, the phone is a personal mode of communication. Your voice is as unique as your fingerprint.