Awesome Idea!
Worth mentioning is that YouTube is actually going to get "worse" over time all due to a new thing "Watch Time" explained by pewdiepie in this video:

This will make youtube videos longer due to content creators willing more exposure and income. But we all know that's not gonna go well since people dislike long videos because they don't have time for long videos. So a new service like YouTube with a reward system would leave YouTube in dust in no time! This would be a great news for our "steemtube"!