It's not about uncertainty, it's about precision. Unless, of course, you think that scientific notation is limited to only high schools.

What do you think the difference between precision and uncertainty is?

'Uncertainty' is a much more ambiguous term that means many more things than 'imprecision of measurement'.

Still, I'm interested to hear why you think sig figs are high-school only when they're the standard way of writing in scientific notation. Do you genuinely think that the example I gave from the video is reasonable? It sounds like you're a theorist and have no experience in real-world application.