When my console throws a NaN I kinda think of it as an Halloween kid receiving a fruit instead of a candy. They won’t say “That’s a fruit”. They’ll say “That’s not a treat”.
I’m personally pissed more often by a falsy 0.
Did you know that early analog computers would literally explode when asked to divide by 0?
Now computers just say “Hey stupid, that shit is not even a Number in a mathematical sense, but sure I’ll add one to it.” instead of “Why would you kill me like this?”
You can’t really define Infinity as a number, yet it is part of their world.
So typeof NaN === ‘number’ totally makes sense in that regard.
If you ever worked with arrays of dates, don’t judge NaN too harshly.