Because this assumes the person is always contactable by email. There is a none zero chance that the person is available for a phone call but not in front of em

Because this assumes the person is always contactable by email. There is a none zero chance that the person is available for a phone call but not in front of email. Instead you see the email 3 hours later, the sender is now busy as are you so you land up in a game of email ping pong trying to arrange a time. Just put your phone on silent or don’t answer it if you’re not available.