I've seen this idea go around a bunch, and I think it makes sense for how a company thinks about product internally.

But it basically makes 0 sense for customers. "Brand" is the exact opposite of a pure function - there's side effects all over the place. Any bad thing that Facebook or Twitter do greatly overshadows the good. Same goes for any other company or flagship product.

This is challenging, because product branding is often championed internally at any company. So thinking about product as "functions" will likely fall apart quickly outside of any engineering org.