Productivity in the economic sense is a measure of labor output, usually measured in dollars or some other currency. But more generally, productivity is how much stuff you get done in a day. Better put, it's how much of the stuff you wanted to get done that you got done in a day.
I've gone back and forth about whether I think "being more productive" is a healthy, humane goal. If we work under the definition I outlined above, then productivity is something to chase so long as the values that you are using to define your goals are healthy.
For example, most critiques of "productivity geeks" are related to the idea that they're workaholics, constantly trying to make another dollar. The critique, then, is not of productivity itself, but of the outcomes that the individual is trying to reach.
On the other hand, let's say my goal was to build a school in a neighborhood in need. Assuming I'm taking ample time to take care of myself (whatever that means to me), most people would applaud the highest level of productivity that I can achieve towards that goal.
Productivity is a measure of output, and realistically, we should be trying to be as efficient with our limited time as we can be. That means taking time to rest, to pursue hobbies, to spend time with family and friends, and to achieve our goals. Managing these things as effectively as possible is peak productivity.
I'm writing this as a reminder to myself. There are a lot of lessons we can learn from people who aren't chasing the same goals as we are. Take the good, leave the bad.