If your goal here is to make money, then yes, if a Hub is not featured it's useless.
In general, a Hub can't start earning a decent income until it's getting regular traffic from search engines. Remember, you are earning only $3 or $4 per thousand views, so visits from other Hubbers, or your Facebook friends, just isn't going to be enough!
If a Hub is not featured, search engines will totally ignore it. Without the search engines it can't make enough money to be viable.
The first thing to do is check why it's unFeatured. If it failed the Quality Assessment Process, then it may be worth revising and improving it to see if you can get it to pass. If it's unFeatured for "lack of engagement", that simply means it wasn't getting any traffic from search engines anyway: in that case, it may be better moved to a blog or other revenue-sharing site where it will be given more time to attract a readership.