> I don't quite understand the issue with aspect ratio. I know there isn't a way to define it well yet, but people have been building websites for almost 30 years without a way to specify it, and now all of a sudden everyone claims to need it. It's weird.

Here is a bit of background on why there is a need for aspect ratio:

https://youtu.be/AQqFZ5t8uNc?t=233