This is also about job security. Technical people often have a record of what they have done. Think commits and PRs. Managers don't have this. Their job doesn't produce anything tangible, this is not to say that it is useless. There are good managers and bad managers, with the majority falling in the latter category.

Being seen in meeting rooms filled with people, talking to them, and pointing to things on a powerpoint presentation can give other more senior managers (who determine their position and compensation) the aura that they are hard at work and making things happen.

This of course is not very strong reasoning.