The only books I ever ordered from Amazon were books in foreign languages and academic books that Amazon apparently prints on demand on behalf of publishers. Books in my mother tongue can only be sold at a fixed price set by the publisher, so there is little incentive of buying from a company that mistreats their warehouse workers.
I regularly borrow audiobooks and ebooks from the library with a couple of taps on my iPhone.
That's clearly inferior to Amazon's service where you can read any book in their catalog at any time, even if a million other Amazon customers are simultaneously reading it, and you can open it and read it as often as you want, with no waiting.
I borrow ebooks from my library quite often, but I also buy a ton of books for my Kindle, for similar reasons as above, and will most likely subscribe to Kindle Unlimited (depending on the catalog — right now the catalog looks like a few bestsellers I've already read or don't care to read, plus several hundred thousand self-published romance novels).
Yes. Yes. Yes. As well as book condition/cleanliness, and being able to keep books forever.
My local library is also only open from 10am-6pm, and closed sundays, so unless I want to take time off of work, my only time to go to the library is on a Saturday afternoon. Usually when I buy a book via Amazon, it's spontaneous because of a recommendation. I'll have a friend recommend me a book. Click, it's ordered and shipping. I'll see a book recommended several times in the same HN thread, check reviews for it, click, ordered and shipping. I don't really remember the book's info in order to look up later while at a library.
Currently I have no idea how to check if a book is available at my branch or a nearby branch. I tried going to the library website and clicked their "check availability" link, and I was brought to a calendar for conference room reservations. Amazon is just a much more polished experience than my library. So yeah, I'll buy a book instead of getting it free from the library.
It reminds me of when people say that services like Netflix, Spotify, Steam, etc are cutting down on piracy because in many cases, they provide a simpler experience than the piracy does. Amazon and books (hell, Amazon and most products) provides that same simplification over a cheaper/free distributor.
Amazon will, from the convenience of any computer (mobile devices included), ship you books from a vast & nearly inexhaustible collection at acceptable costs.
Now the Unlimited plan brings you both for $10/mo: beyond-library-scale of practically free books delivered instantly, and bringing you in close proximity to darn near every book ever written available at modest cost in 2 days.
Heck, many subscribers would pay more than $10/mo just in gas driving to the library.
Licensing, not selling. Unless you were talking about dead-tree versions.