I think it depends on the health conditions.

I just need something to wear on my left arm that states or directs to information in my wallet regarding Tick Anaphylaxis and No BP or Needles.

I really don't want a third party company having all my "verified" (whatever that means) medical details. That's just me. I don't even let the Federal Government have access to that information as I opted out of their generous (cough cough) suggestion to have all my medical history/information in one place.

I just looked up the pricing of the MedicAlert memberships here in Australia and they charge $49 per annum and they say that they keep your "full medical story" on file. Illnesses, Medications, allergies, devices etc.

Not for me.

My GP has my medical history on electronic record. My hospital has my medical history on electronic record but it can't be accessed by random people. There are checks and balances to make sure of patient confidentiality.