Or if your browser unloads the page to save memory (it helps that every additional page increases memory footprint!), or crashes, or you want to bookmark your p

Or if your browser unloads the page to save memory (it helps that every additional page increases memory footprint!), or crashes, or you want to bookmark your place and come back later, or you're looking for a post by date, or a million other reasonable scenarios. Endless pagination only makes sense if you consider content after ~4-5 pages to be near worthless and don't intend for people ever to read it.