There's this thing called video compression, and it's gonna work pretty well for something that's mostly a still image with just a mouth moving. If anything, it'll compress that kind of thing the best compared to other kinds of content, like sports or games. Like, if anything, gameplay recordings are probably the worst type of content in that regard, needing the most bitrate and bandwidth to reach any kind of fidelity, and always looking bitrate starved with h264 (and likely even with newer codecs if it's at lower streaming bitrates).