That. It sounds less boring if everything isn’t called “X street” and “Y avenue”. Boulevard has typically meant a big wide main artery road, but it could also mean whoever named it thought that sounded cooler.
I’ve lived in places with grids where “streets” and “avenues” were the same thing, but N-S, E-W as previously mentioned, but that’s a local thing some city planner came up with for that area, not a general rule in English.
Unrelated to your actual point, but I swear I’ve seen cars trying to get through that street. It’s… not smart to get your car stuck in that mess, but I don’t think it’s outright prohibited. (Or maybe I’m thinking of the next street over)