Witchcraft a religion

That is one definition, yes. The definition of witchcraft and magick are not the same per se.

Magick can be used as an explanation for nature, and is believed to be able to apply the laws of nature and bring about change, via methods such as energy manipulation.

Personally I like Crowley's "Magick is the science and art of causing change in conformity with ones will." That could be interpreted as internal, external change, or both.

He defined every intentional act as a magickal one, writing a book, reading poetry, opening the front door in the morning- it all creates change in your personal universe.

Yes,indeed. Magic is the changing of one or more things into something else. My witch teacher talked of Natural magic, and Applied Magic. She would give an example of Natural Magic as the changing of a caterpillar into a butterfly; and Applied Magic as such as making a potion for healing from two or more Herbs.
She taught me that "Magic is the knowledge of the few, for the benefit of the many."
To her, radio and television are magic.