I don't think it is much different.
Let's think it through. Person with standard anxiety is terrified that their flight might crash. They accept that they are scared but logically it's unlikely but possible that the plane will crash so they get on the flight anyway.
Person with health anxiety is terrified that their headache is a brain tumour/ mole is skin cancer. They accept that they are scared but logically it's unlikely but possible that they do actually have a brain tumour/ skin cancer, so they decide not to go to A and E/ ring the GP that day but decide to go about their life and re-evaluate their headache /mole in the following days.
The thing with health anxiety and other types is that there is always a nugget of possibility that your anxiety was right, and your plane will crash/ your mole is cancerous. But 99.9 percent of the time that isn't the case especially with health anxiety where you have become hyper aware of your body or your child's body and are over analysing and catastrophising every symptom.
It's the same in that your way of making the anxiety go away is to get a doctor's opinion. But 99.9 percent of the time there wasn't anything seriously wrong and it was your anxiety telling you you needed that expert opinion. This method is trying to get you to hold off on seeing the doctor for every twinge, but to live with it for a day or two and see if it really needs a medical opinion.
Of course medical emergencies do exist. My happy middle ground is to try to be logical and occasionally I seek an opinion somewhere like here as a first step (did so this weekend with my son actually. Ended up not needing to see the doctor and he's fine now).
At least that's what I think.