"Productive" has a greater focus on high quantity; completing a great number of tasks. "Effective" focuses more on high quality; specific acts which most efficiently advance towards a particular goal.
The ability to create in abundance may be a good thing as long as it's directed towards a specific goal. I can dig holes in my yard and refill them all day long. We can argue that I was "productive" but was I actually "effective"? Not so much unless my goal was to provide a playground for gophers. Doing more of something doesn't guarantee energy well spent.
One might say "It's just semantics". However, words are incredibly important because they shape how we think and how we express ourselves. They influence our perceptions, biases, thoughts, and arguments. Words enhance (or weaken) our ability to communicate with and influence others.
Is it possible that we use "being productive" as a disguise or rationalization for "busy work" which doesn't actually accomplish any specific goal? Here's some good news. There's a great way to help maintain focus and avoid unproductive "busy work": Use the word "effective" instead. This way, it's more difficult to rationalize productive, but ineffective behavior. Thank goodness for boatloads of improvement