If I am on twitch I do make use of the MIC because people appreciate the mic based gameplays. And in case of youtube I focus more on editing when I upload videos. But with new guidelines I make sure to also add voice to youtube based videos.
I want to say it's one to one, but in all honesty I'm a bit fuzzy there. I can recommend JoyFreak's sister site AdminIntel - Admin & Webmaster Resource where there are lots for people of varying degrees of expertise with development, you likely can get a far more precise answer there!