I occasionally use Firefox's equivalent feature for creating a stock browser to troubleshoot things, but I'm not a webdev, so that's usually rather to troubleshoot whether my array of tracking protection, cookie blocker etc. addons is causing the webpage to irreparably break, or if it's just the webpage that is broken (or both).

For general use, I just don't have separate enough use-cases to weigh up against the organizational overhead. Most of my entertainment-stuff happens in RSS Readers anyways and the rest is pretty much just programming-related, so can all stay together in one browser profile...