You created a backlink for that YouTube creator, which helps him out, but can also help your blog if it causes you to become an authority on that subject.

Over time, he may even notice you linking to him and start checking your blog out and creating backlinks to you.

When I blog, I always keep Google, Yahoo and Bing in mind. Even if I don't get a lot of upvotes, I know I'm helping Leofinance and Hive to become authority sites in the process.