In Chromium browsers which tend to stick to the defaults like Avast Secure, Chromium, Chrome etc, you can say make www.youtube.com into a mini app by pressing the 3 dots and pressing more tools and create shortcut as and then saving the settings and opening the app.
I've noticed this feature does not appear in Opera and it's such a useful tool to open your favourite sites and not opening the main Opera windows with tens of tabs slowing you down.
I think this is a big feature that Opera doesn't have yet and I think it will be welcomed.