My surgery started telephone appointments well before Covid. You ring at 8.00, as does everyone else who needs an appointment, if the line is engaged you keep trying, usually until you have missed the last telephone appointment, in which case you try again the next day.
Working people are likely to be commuting at 8.00am, so the chances are they will have to decide to be late for work in order to try to get an appointment, and this could go on for days until they actually secure one.
If the receptionist is happy to let you have a GP appointment (and that is a whole other thread in itself) you have to wait for a callback. They don't even give an approximate time, so unless you don't work and live alone, or work and have an office to yourself, the chances of this happening in private are slim. Parents may be discussing personal matters in earshot of children, workers in front of colleagues, a pregnant daughter may have to take a call in front of an abusive father, and so on. The concept of patient confidentiality goes out of the window.
If you have internet access, you can try to book a telephone appointment online, but these are very limited, and if you don't do it at midnight or very soon after, you have no chance of that, either, and you still go on the list for an appointment with no time attached.
The GPs themselves are very good, as are the nursing staff, but it is clear that they are overstretched. We have lived here for over 30 years, and the service has been cut back massively.
There used to be home visits available for children or the elderly, Saturday 'turn up and wait' appointments for those who couldn't easily get time off work midweek, same day appointments, continuity of care with a doctor who knew you, and so on. Now, the policy is to refer as many people as possible to hospital consultants, who operate in silos so there is nobody with an overview of a patient's care, and people rarely get to see a GP, never mind get to know one.
A telephone appointment can be a good thing for all the reasons people have mentioned on the thread, and they are possibly ideal for the retired or otherwise non-working people who live alone, but they should be an additional service, with face to face appointments available to those who need privacy and to have their symptoms examined.