If its not a convenient time you just say give me 15 minutes while I find somewhere more private.
But that means yet another phone appointment slot taken up. Plus as pp said, some people can't take phone calls at work let alone pop out...eg sole adult in charge of 30 six year olds, with no TA and no idea when a phone call will take place, as another pp said. School has a no mobiles in class policy for adults due to safeguarding.
Even if that was possible, it would be tricky and highly inappropriate to say the least to discuss how I was doing with regards to depression, self-harming and work-related stress whilst standing in the playground. In the past I could simply arrange a f2f appointment with the GP for a specific time (every two weeks for the first few months after returning to work) and let school know cover was required for those times.
Pp who said talking about symptoms over the phone was the same pre-pandemic...not necessarily. No phone appointments here until Covid, just the receptionist and yes, you did need to give a brief description. But that's v different to a full on consultation. And as teachers struggle in to work come hell or high water, any teacher ringing for an appointment is either off as very sick so at home, or ringing in the holidays from their home. Private in both cases.
What works for some people does not work for others. But I am concerned that overworked GPs will grab onto phone appointments as a miracle solution but actually it will lead to some things (people) slipping through the net.