[jeroenhd]

There's a 5% range when converting mass into weight (depends on where on Earth you are). Santa loses a few kilos when he comes down to the equator. It's not enough for people to care, but it can be important if you're building something that needs to carry a lot of weight.

This is a very important distinction to make in scientific papers. Completely meaningless for most writing. If anything, physicists got the definition for the word "weight" wrong and patched up their mistake by adding the concept of "mass". Most mass is measured standing still on earth, so "weight" is fine unless you need to be precise.

[kelnos]

> It's not enough for people to care, but it can be important if you're building something that needs to carry a lot of weight.

The problem is that the article presents these "corrections" without being clear what context they're important in. The examples given make it sound like the author is railing against people who use these forms in regular conversational speech. And even the longer explanations after the table still make it seem like the author isn't only concerned with formal/scientific writing.

So yes, in scientific papers, I do think this list is a reasonably good guide (though good luck getting particle physicists to give up electron-volts, or people writing about electrical power systems to give up kWh). But for everyday use it feels unnecessarily nitpicky.

For the specific mass vs. weight example, especially, regular conversation (spoken or written) is pretty much always going to use the term "weight", and using "mass" would feel stiff and unnatural.