First it depends on what you have. If you have a smart phone, tablet (iPad or Android), Kindle or a computer (laptop or desktop), you can see text based books on all of them because you can change the size of the text to match what the device displays and you require.
Not all devices that can show a Kindle book can show graphics or show color. Kindles use an amazing technology called "liquid paper" that works like regular paper.
What this means is they do not require constant power to display a page and they work MUCH better in bright light. However when you want to read a page in the dark, you need a light source to see the page just like a printed page. Kindles tend to be more specialized devices, designed to be used for readers, which tends to mean lower weight and radically longer battery life.
By contrast, iPads and Android devices are much more flexible in what they can do (including color graphics and movies, better sound, and color).
It is all about selecting the device that makes the most sense for what you intend to use it for. Do not choose a hammer to put in screws. LOL