Perhaps for people that want to grow their roles in organisations, it's important. As a freelancer, I am happy to live without this ritual. In the past, before I became freelancer, I dreaded these reviews, as I suspected often these performance reviews could be politically charged and not necessarily deal with my performance (for example a manager might tell me I need to improve some aspects for a raise - I might have to suck up to some manager to get more chance for a big raise, when a limited budget is available for a group of employees).
As a freelancer I am free to decide on the aspects I want to improve on and as such I don't need a manager to help me with this. This makes me much happier.