Minor Goggle syntax question

In Goggle rules, is there a reason to prefer /r/rust/$boost=3,site=reddit.com over |https://reddit.com/r/rust/$boost=3? The example Rust Goggle has a lot of entries like this where instead of using a | syntax, the URL is split into the site and the rest of the URL. (Eg.: /easy_rust/$boost=3,site=dhghomon.github.io for pages under https://dhghomon.github.io/easy_rust/ , /tracks/rust/$boost=3,site=exercism.org for https://exercism.org/tracks/rust , etc.)

The Goggle consistently uses only the site= form and never the | prefix syntax, even when the URL segment it’s attempting to match is an exact prefix.
I’m just wondering if there’s a performance implication or some other reason for this, or whether they’ll both work fine for such cases.

Another Goggles question: are the patterns case sensitively matched? Would /easy_rust/$boost=3,site=dhghomon.github.io match https://dhghomon.github.io/Easy_Rust/ too if such a page existed? If not, what’s the best way to achieve case insensitivity?