You can have a face-to-face conversation with a friend, but how do you do that if you want to talk to a therapist? No therapist is gonna make an exemption and leave their phone in another room, not to mention, they literally write their notes into the computer system, instead of on paper.
And with lawyers? I just read about how Luigi Mangione’s conversation with his lawyer is being unlawfully recorded. How do you even have a conversation with your lawyer if you are in custody and they could just hide recoding devices all around the jail?
Sure, maybe they can’t use the evidence in court, but they could just leak an out-of-context audio clip to the press to win the “court of public opinion”.
You can (and some do) insist, that all phones and other digital devices be left outside or out in a well isolated place like a fridge. Furthermore you can use methods of encryption for both physical notes and digital notes. Neither is completely safe from being compromised, but then again hardly anything truly is.
If you want to be fairly certain to not be monitored, always leave digital devices behind and have meetings in varying locations with few or ideally no other people around. Only discuss confidential information with people you know and trust. Even then, experience from places like East Germany proves, nothing is truly safe from being compromised if enough time and energy is spent on the issue.