Let me explain. I ride motorbikes. You don't want to be using WD-40 on the chain as it will strip it of any existing lubricant and dry it out, which as you can imagine, is bad. However, it's actually really useful for cleaning parts of the bike that have been covered in gunk and grease.

I have to admire their marketing, as like you mentioned, I grew up in a house where WD40 was used for absolutely anything sticking or squeeking, and so for the longest time also used it to fix those things, and beyond.