Containers aren’t an alternative to serverless computing. That’s like saying “roads are a scam, I’ll just drive my car instead.” The only serverless compute service they mention, Lambda, literally allows you to deploy custom containers.

It’s not the same, and you kinda answered your own question with that quote. Consider what happens when an object defines both dunder bool and dunder len. It’s possible for dunder len to return 0 while dunder bool returns True, in which case the falsy-ness of the instance would not depend at all on the value of len