I wouldn't say I try everything I see online, but this idea of using MAC's paint pot in the shade Painterly as a concealer did intrigue me. A lot of great makeup artists will also tell you to not limit yourself with the primary purpose of the product, it really doesn't have to be by the book, you can experiment all you want.
You know how we often hear that in the ''beginnings of makeup'' everyone used products for many different purposes, for example lipstick for both lips and cheeks and mascara for eyebrows as well.