Do you need a kindle to download books on Amazon?

Here is a variation of a question I got asked recently.  "Do you need a kindle to download books on amazon?"

The answer is no.  You can download books from Amazon to a large variety of other devices: everything from a computer to a phone.

In particular, I was asked about an iphone.  I was able to find directions here: http://www.amazon.com/gp/help/customer/display.html?nodeId=201244870.  I don't have an iphone though so I wasn't able to test out these directions.

Downloading to a computer is really easy.  You basically just buy the book and it downloads automatically.  One challenge I found on the computer is that it can be challenging to find the reader on a computer.  One solution I came up with was just to download a free book and it will come up automatically.

I'm not sure why Amazon has made it so easy to download to so many devices.  Perhaps Amazon found that selling books to a larger audience is more profitable than selling kindles?  If any one has insight into this I'd be interested to hear your comments!