12/15 fps is actually insane, thankfully nobody saying that is gonna be in a position to make those kinds of decisions. (and there are some things that do stream in 15 fps, like 1seg ... which broadcasts tv on a mobile phone screen, and not a smartphone, a tinier flip phone, like 3-4 inches. and it's really more of a technical limitation for a technology and phones from 20 years ago. and youtube can serve 12 fps ...at 144p.) Even for literally just watching someone sit and move lips, 24/30 is gonna look much more natural and believable, and not be jarring unlike going down to that low fps. Like, have you actually watched any 12/15 fps footage of people talking recently? Cause it's not gonna be giving what you think it's giving. It's not gonna look "fine" even at crystal clear 1080, making it feel like a shitty zoom call that might as well be in 240p. Unfortunately there is a reason why it's not a cool and totally useable life hack to just crank it down to 12, because it just looks bad. Some people in these comments really seem to be just saying things before they even try and see them with their own eyes.
https://news.ycombinator.com/item?id=49455895