I was watching a YouTuber yesterday and he was talking about putting on a YouTuber voice and how it’s an exaggeration of yourself. So I could definitely see how she would have a voice to put on for seeming more cute and bubbly where I think her voice in that clip is less fun because it’s more realistic of a regular person.
First, in that clip she just sounds phlegmy like she is getting over a sickness. I'm sure you have also experienced the deepening of your voice that comes with something like that.