With our priority of giving doctors a way to have their data be usable offline, the built-in features of iOS automatically passes security standards compared to Android devices.
Another priority we have is to make consults more personal. Having a computer in the middle of you and your patient is not the best thing for a doctor-patient relationship.
Having a tablet or iPad minimizes the screen time, it makes you more mobile, it adds ways for you to do notes and you can even share or present on it to your patients. It's just better than a computer.
Nothing is stopping you from using a computer though. You can always access SeriousMD on your computer if you need it.