If you are a YouTube gamer playing as some kind of non-human character then it might make sense for you to use a voice that suits that character for your voiceovers.
There are a lot of reasons you might want to change your voice in a YouTube video. You can change your voice for comedic effect, or to mask your identity. There is a lot of software out there that can make you sound like a completely different person.
Your vlogging voice is usually a louder version of the way you always talk, but in some situations, you might like to try out a completely different voice.
