It's a theory I've got, the closer you get, the more comfortable you are with your subject. Got your folks that always like to shoot from across the street, their subject unaware, unable to participate or even grant permission.
Got your folks, like to get in real close. I'm one of those folks. I like the intimacy of it, like to be able to interact with my subject in that close space, make it a communication, a partnership.
Yeah, I could get this same frame from a long lens. The way I look at it, it's just like that. Closer you can get, better you are. Able to be in such proximity to another person and have them comfortable, not raising any alarms.
Then it's you affecting what you are observing. Participating, versus merely being a voyeur.