They’re talking about using Fahrenheit in a day to day capacity like for the weather, not as a scientifically rigorous definition. 0°F is very cold and 100°F is very hot. If you treat it as almost a percentage of how “very hot” it is then it can be a pretty good indicator.
Don’t get me wrong if I had to choose between all of metric and all of imperial then I’d ditch Fahrenheit in a heartbeat, but it’s not often in my day to day life that I think I’d ever use any temperature outside of (approximately) -15°C and 35°C. Therefore Fahrenheit in that specific regard offers more granularity and a nice 0-100 type of temperature scale for the temperatures I’d see on a day to day basis.
In terms of distance and weight I feel that both systems offer equally arbitrary (to daily use) units. There’s no fairly universal thing most everyone would experience in terms of either weight or distance that could be usefully measured on a similar 0-100 scale.
People working more industrial jobs are probably going to be more frequently dealing with things that weigh a significant amount than people working office types of jobs so no standard would satisfy both groups. The closest I can really think of is the weight of an average person, but that’s variable based on region, has changed significantly over a short amount of time, and is very rarely ever a weight that most anyone would need to deal with, therefore wouldn’t be very useful or relatable to most people.
Distances offer the same problem, since there’s no singular distance that the majority of people are going to experience by which we could base a scale on.
That being said, I feel that weather is a fairly universal experience for everyone and a scale that fits all of the most frequently used values (for the weather) in the 0-100 range is quite nice.
I’m fully aware that the weather isn’t the only use of temperature in a day to day context, however it’s not often that I need to know how hot the inside of an oven feels. Therefore how far exactly it lies beyond the 0-100 very cold to very hot spectrum that Fahrenheit offers doesn’t really matter.