I see Affinity has their products on sale for $24.99 (one time). I bought Publisher, thought it was cool, and bought the two companion pieces. They integrate very nicely. If a Youtube search has any bearing on reality, it looks like at least some professional designers are moving away from Adobe to Affinity. To my sweaty, knuckle-dragging, eyes, Affinity looks like a worthy replacement for Adobe. Affinity Publisher doesn't export to epub, but I'm OK with that. It looks to me like the power of a full desktop publishing utility is a little lost on creating an ebook. Vellum is quick and easy with great templates, but I'm curious. Is there anything really wrong with the epub output from Scrivener? What else do you need?
I already had Affinity Publisher, as it turns out, and I just bought Affinity Photo. What does Affinity Design bring to the table?
You're right -- I don't think I do. And for the rare occasion when I might need a vector graphics program, I have the predecessor to Affinity, Serif DrawPlus. (Which isn't currently installed, and I probably should find out if it even runs under Windows 10.)
I got an Apple Pencil yesterday. That lets me use my iPad as a second display/digitizer. It works well - makes it quicker to mask out a background, for example. Cool stuff!