YouTube is probably one of the parts of the internet I consume the most, so I was more than a little sad when YouTube announced that they don’t have plans to build a visionOS app, and disabled the option to load the iPad app. This leaves you with Safari, and the website is okay, but definitely doesn’t feel like a visionOS app. Couple that with visionOS not having the option to add websites to your Home Screen, and YouTube isn’t that convenient on visionOS by default.
Also it’s a css JavaScript skin over the actual YouTube website with some video player integration.
It’s not like the whole interface is from the ground up.