Talk to your doctor / GP. Mine told me that he has to choose what goes on the myhealth record and it’s not as simple as everything goes.
If you’ve got kids for example, you may wish for the doctor to tick the asthma checkbox for example for their own safety.
It’s about sharing the data for your benefit, like when you’re retired and away in Qld with your caravan and you have a health episode - quick access.
All that being said... I opted out.