The ability to play the game is part of being a good engineer. That doesn't mean you have to out-do the sales team for outgoingness or anything like that, but you do have to be able to persuade people of the rightness of your ideas. That's will never be a purely technical skill.
It's all related. Your effectiveness depends to some extent on the people who work with you (both up and down the org chart) and the problems you work on. Unless you work solo, charisma matters as much and maybe even more than other hard skills.
