I agree with you, I also hate when websites hijack standard keyboard shortcuts. Altough I don't see this being the case: as it requires touch events, and even if you're on a touch-capable laptop or desktop PC, it won't override much (maybe the native pull to refresh from Chrome, at most).
Also, what I said in a previous comment: maybe you want consistency across browsers/platforms or branding, customizing how it looks. And maybe you don't want to refresh the whole page, maybe just one section calling a JSON API, or perhaps you have a heavy job that requires a worker.
Also, what I said in a previous comment: maybe you want consistency across browsers/platforms or branding, customizing how it looks. And maybe you don't want to refresh the whole page, maybe just one section calling a JSON API, or perhaps you have a heavy job that requires a worker.