Indoor cats get bored; In fact, probably everyone gets bored when it’s subzero outside. That said, a bored house cat can make the life of everyone else much less boring, very quickly, so it’s worth avoiding.
In order to avoid the consequences of cat boredom (we have two, and they are young), I braved the cold weather to set up the cat enrichment center. In other times of the year, the shepherds crook hosts a hummingbird feeder. In cold weather, I’ve installed a suet feeder.
If the bird feeder was for me, I’d be disappointed. Even with bird identification taking place in the same part of the brain as faces, and thus being extremely difficult for me, I haven’t had any trouble. This is because there is precisely one bird that attends the feeder. It’s a Flicker.

The cats don’t care. They aren’t bored by it. They sit in the window, tails lashing, and watch the thing for hours.
I’ll admit that the bird feeder getting the bird to (finally) stop knocking on the house and waking up the dog feels a little bit like providing a payout to a protection racket. That said, he’s also providing my cats with considerable entertainment.