Because working hard is not important if it has no impact. I've had people work really hard, I tell them to make sure to do blah, and to focus on blah2, and to let people know that they did blah3. They ignore that and just work on what they think is important, and work super hard.
Then eventually people realize what they did is a bit "offtrack" and doesn't connect to an existing system that everyone agreed is going to be the base platform going forward, and it's also not immediately useful because it didn't focus on blah2, and it doesn't cover this use case that everyone else cares about (but that they don't think it's a big deal), and other people don't ever figure out it does blah3 because they never documented it properly and used a less familiar term for it. Also, everyone is now stressed out, because what this person did now needs to be replaced in way less time. Well then, all that "value" they produced was just a waste of company money, frankly.
So yeah, I would promote the person that worked less hard, but was well connected to figure out what others care about and is important to the company, and made sure that piece worked great. And the person that produced less, but enabled others to produce more (either from a technical standpoint, or a morale/assurance standpoint) so overall the output was greater. It's a no brainer.
Also, people who are constantly thinking about their own productivity can be dismissive of others, creating a bad work environment. So you don't want to elevate those behaviors.
I think the person is talking about cases where working hard had a big impact, but the person did not benefit from it.
This is fairly normal. The only job I had where this wasn't the case was the one where the manager and his manager had grown from within - had worked on the same stuff we had, so they knew the ins and outs.
In all other cases, it's a manager who came from another team, and while they were very technically competent, they had never done our job. They usually were not in touch with what was needed to get the job done, and placed little value on much of the labor needed to get it done. This usually leads to team members manipulating their way into getting someone else to do the real work so they can do their manager's pet project. They get the promotion, even though the pet project dies soon after, and the folks doing the bread and butter for the team stay where they're at.
This straw man is the thing you fall back on to rationalize not working hard and not caring, just playing politics and taking credit for each other's work?
Then eventually people realize what they did is a bit "offtrack" and doesn't connect to an existing system that everyone agreed is going to be the base platform going forward, and it's also not immediately useful because it didn't focus on blah2, and it doesn't cover this use case that everyone else cares about (but that they don't think it's a big deal), and other people don't ever figure out it does blah3 because they never documented it properly and used a less familiar term for it. Also, everyone is now stressed out, because what this person did now needs to be replaced in way less time. Well then, all that "value" they produced was just a waste of company money, frankly.
So yeah, I would promote the person that worked less hard, but was well connected to figure out what others care about and is important to the company, and made sure that piece worked great. And the person that produced less, but enabled others to produce more (either from a technical standpoint, or a morale/assurance standpoint) so overall the output was greater. It's a no brainer.
Also, people who are constantly thinking about their own productivity can be dismissive of others, creating a bad work environment. So you don't want to elevate those behaviors.