I agree up to a point but don't think that lines up well with this affiliate business model. Producing what you are passionate about, sure, following an ever changing SEO landscape and constantly tweaking in search of conversions, much less likely to overlap with the hobby as job passion model.
I'd like a good balance of the two, I suppose. If I could earn a few coins while learning and writing about things I enjoy, I'd consider it a successful venture. I'm thinking about Amazon specifically because I'm an avid user/addict.