I don’t subscribe to Premium, so I can’t guarantee if the improved bitrate makes much of a difference. But YouTube says that enhanced video quality turns on automatically “based on your connection and viewing settings,” so if you pay for Premium and your videos now look a little better, that could be the reason.
YouTube also detailed some other improvements that are now available to Premium subscribers. You can now pick up videos where you left off when watching them on smart TVs and tablets; Previously, this was only something that could be done when moving from mobile to the web. Premium subscribers will also be able to try out YouTube’s experimental conversational AI chatbot and AI-generated video summarization features.