And so far the explanation in the article is the best I found, not least because subnormal numbers appear naturally.
There is a mathematical foundation behind it of course, but it is not easy for a programmer like me. I think it is better to think in term of bits and the integers they make, because that's what the computer sees. And going this way, you get NaN-boxing and serialization as a bonus.
Now, I tend to be most comfortable with a "machine first", bottom-up, low level approach to problems. Mathematical and architectural concepts are fine and all, but unless I have some idea about how it looks like in memory and the kind of instructions being run, I tend to feel lost. Some people may be more comfortable with high level reasoning, we don't all have the same approach, that's what I call real diversity and it is a good thing.