Sadly I think it is being used wrong...
IBM is focusing on using Watson to cure very specific diseases, like certain types of cancer.
I think a far better use for Watson would be to do initial diagnosis, for example my life got massively delayed because I got hypothyroidism as teenager, but only using internet data I could self-diagnose and self-treat (because doctors are still unwilling to help, not trusting data, and before someone come berate me for self-treatment, it is working...) as adult I could finally get my life 'started' (hypothyroidism affect physical and mental development, and slows down metabolism and the brain)
During my quest I met many, many, many people on internet, that had self-diagnosed with something using the internet as a tool. All of us would have been diagnosed properly if Watson was being used on the doctors office, using its data crunching capabilities and symptoms as input to find out what problem we had. (in my case: I have Hashimoto's disease)