“A phone call is preferred when calling out sick”

Is this said by bosses so that employees won't be able to have a text-based record (screenshots of texts) in case something rude/inappropriate/illegal is said regarding a call out? I prefer to text my call outs because when I am sick and feeling like shit and have a sore throat the last thing I feel like doing is getting on a phone call to my boss where they try to guilt me.