From what I can tell health is about both quantity and quality. 30 minutes of exercise and sitting is not good for health. That is why 10,000 steps per day is so often a goal - I can do a few thousand steps in the 30 minutes of exercise, but other activities should also give steps and I want to know in general how active I am.

Step tracking is for people who like to pretend they are doing something healthy without actually exerting any dedicated effort above and beyond their normal routine.

"Walking briskly for 30 minutes" is a better measure of something healthy than how many steps you took.

But that doesn't give me data...

I do try to get my daily exercise. However it is still interesting to know how many steps I've taken. (sometimes my daily exercise is bike or swimming which are obviously not steps)