I do think this is one of the most passive ways, however. Unless your site is receiving god-like visits (>100,000 monthly) it's going to be very hard to get the casual visitor to actually convert into a sale via the affiliate program (considering the Law of Averages).
A part of the puzzle here (that I'm presently figuring out and actualizing) is if you want to fully receive financial gain, some of the effort with be with being the "pushy saleswoman" see article below section 4:
6 Mind-blowing Secrets The Richest Bloggers Won't Tell You
Some of the "Elites" might get mad I'm spilling the beans…
I do think, however, even writing that comes with a false stigma and is a bit of a misnomer.
The core of everything that you're doing with your blog was probably a result of something deep down within you — perhaps even on a spiritual level.
I know for me, my mission with my blog is to "help 1 million people become their own boss by blending their passion with their career — and this is done through blogging."
Even with the audacity of helping 1 million people, I truly believe in my mission. Through that, even when I feel "cheap" and "annoying" I can come back to why I'm doing this in the first place (I could go on a Gettysburg address on how I believe automation and AI in the economy and people are going to need to fill an achievement gap displacement with human creativity and ingenuity — and that can be done through blogging).
In any case, I hope I didn't get off track with your comment. It just really excited me with possibilities that are with us all!