And I imagine that some websites might do things that take a long time, like a heavy upload, download, or something that takes a lot of processing (e.g. loading

And I imagine that some websites might do things that take a long time, like a heavy upload, download, or something that takes a lot of processing (e.g. loading a game). In those cases, I would think that people would rather just have them keep working in the background while they focus on other stuff.