I haven't used Bottle, but it's definitely a micro-framework. It doesn't do much beyond URL routing and a very basic template language. It doesn't have ORM, forms, authentication, commenting... all these have to be provided by external projects. With Django, you get all that included.
Now sometimes the Bottle (or Flask, or any of the other micro-frameworks) is what you want, and you don't need all that extra stuff. When you do, though, Django is a better way to go than building your own.
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DR.