Potential security issues:

1) You are going to be asked authorize Very Necessary Medical ID to gather information about you, including "current medical conditions, doctors treating you, any drug or food allergies, and more about your personal medical history including insurance carrier, etc.etc.etc..."
2) They will "Link to a secure and confidential database where your health care provider can access all your medical records.....etc.etc."

I have some experience with the issues regarding medical records, the electronic privacy act, and HIPAA. I think the protections under those statutes are insufficient, and I doubt that the cited company is even a "covered entity".
Therefore, I have little trust for their "secure and confidential" database. If you want me to drone on and on about the potential abuses of others' access to your data, that can be another thread.

My point: anything of significance... you can obtain and you can be the "custodian" without putting this all together and risking it being hacked. MedicAlert is sufficient.