Say you went blind in one eye, and technology became sophisticated enough to replace it with a robotic one that interfaces with your nerve directly. The doctor offers you two options: a regular eye that you can see normal wavelengths with, OR an infrared eye which allows you to see the infrared spectrum. Keep in mind, this is only one eye, so what you see would most likely be a composite of regular vision and infrared vision.
Personally, I’d probably take the IR eye. Partly because of the geekiness, and partly because of other applications. I could see better in the dark, I could see when objects are hot, and so on and so forth. On the other hand, I’d be giving up depth perception, but since I had presumably only been living with one eye for awhile, that wouldn’t be much of a problem. And if I was in a situation where I didn’t want to see in IR, I could just close one eye, or put a patch over it for that sexy pirate look.