In this answer, Stan argues that having the choice between many focal lenghts in a large range is essential for studio photography, making a zoom lens a good choice.
This was surprising to me as a beginner, since I'd assumed that "zooming with your legs" would be completely sufficient in a limited space. In the same vein, It's always sounded strange to me when focal lengths of 100mm or more are called "portrait lenses" when a portrait is supposed to show a person the way another human interacting with them would see them - and isn't that what a normal 50mm focal length does?
Now I do know that the focal length influences not just the angle of view but also the way objects appear relative to each other, but I guess I've never really considered it relevant except in extreme cases.
The dolly zoom demonstrates pretty clearly the technical effect, but are there example pictures or maybe even a tutorial that shows it in terms of artistic image composition?