Question For List Builders. Is My Niche Worth It?

Just looking for general guidance so I don't start something I won't actually use. I have a couple of projects and I'm considering putting email opt-ins on my sites. The sites are entertainment based and do good volume so I'm wondering if it's worth creating email lists for them because of the niche.

I always hear the money is in the list but I'm not certain that applies to entertainment, funny, viral stuff. I personally wouldn't want an email about that but I wonder if there is some value that I may be overlooking. Any advice or experience with this is appreciated.