It’s important to balance an individual’s individual competence vs their effects on others.
If working with a competent person means the rest of the team constantly feels stressed, bullied, aggrandized, looked down on, or whatever else then those people are less likely to perform to expectations which may have more of an impact than the competence gain.
As long as that person is being tactful, there's no reason the rest of the team should feel stressed. Work should be an environment where people can learn from each other, a meritocracy where people get rewarded for results and being the best they can be.
But this is sadly not the case for most workplaces, so why bother working hard? Just do the bare minimum and play politics.
If working with a competent person means the rest of the team constantly feels stressed, bullied, aggrandized, looked down on, or whatever else then those people are less likely to perform to expectations which may have more of an impact than the competence gain.