Well, yes and no.. I do use the backlight on my Kindle if it's dark, but this changes how it looks. I have a Paperwhite Kindle. With the backlight on it's more like reading on LCD, though not as bad. The Kindle looks much nicer if I can use a bedside lamp instead of the backlight, just as I would with a paper book.
There's a tiny amount of light, yes. I don't know why Amazon made it that way. It's not really visible.. not to me, at least. But it's probably one reason the battery is slowly drained, over weeks, even if not in use.