Although we abstract away PDO in most cases it's good to know about how it works. You will be interacting directly with PDO from time to time and there are some things you should know (spoiler: setting a few defaults is necessary).
We want to develop features with an API-first mentality. Everyone developing for Vanilla should undersdand how to design a RESTful API endpoint so that we can have a common language for feature design.
Vanilla is moving more and more onto the client-side and our javascript needs to be as well programmed as our server-side code.