Canva for Authors: why bother?

When my first book came out, I expected the publisher to do the marketing. (Ah, baby author me was so naive!). Turned out that was wrong. Where were my lovely marketing graphics that I could share on social media? How come other people got photos of their book covers on bus stops and on billboards? What was going on?

Eventually, I figured out that those cool images of your book on a billboard were mock ups and I found out how to make them. You used to have to either use Photoshop or fiddle ar...