Medical data is your test results from check ups and scans, biopsies, blood test etc. That is the data you input in Skychain. Skychain will analyze the data to give you a result. But data will become cheaper in the future because of technological advances anyway.
Skychain is the logical next step in medical advancement. A supercomputer if you will, to give you a more accurate diagnosis from your tests.
Doctors will still be around, but this will be a hell of a good tool to help them.
Think of Star Trek , when one day you go to a lab and the computer tells you whats wrong with you. This is it...