Consumers use YouTube as a tool. They use it for research, entertainment and inspiration. People now watch TV programs on YouTube and stream YouTube content on TV - on demand. This 'on demand' aspect of YouTube has made online video more dynamic, more popular and more profitable for brands than TV advertising. Purchase intent is 150% higher from paid YouTube TrueView ads than from TV ads. Consumers are given an easy call-to-action (e.g. Explore More, Purchase Here, Book Now etc) as they view content. Above all, ROI in YouTube is measurable. Brands have real-time access to video views, clicks and purchases. So in the battle of YouTube vs TV advertising, the winner is the one that can deliver to consumers and brands.
Source: "YouTube on TV or TV on YouTube? The Blurred Lines of Online Video Consumption"