Do you consider 4K TVs are worth it right now? I remember when Plasma TVs came out they were really expensive, and to be honest they were proven to be pretty bad really soon. Now this is a new thing... maybe it's another exaggeration? Maybe it's just another trend that'll disappear as soon as the next one comes by?
Eh, not worth it right now, no. There's a minimum of content that can be played in native 4K resolution, and there probably will be for next few years. 4K monitors I would say yes, because you can actually play videogames in 4K native resolution if your PC can handle it, but TVs.. it will take a long time until you can even utilize them.
4K resolution doesn't make a difference unless you're farther away from the television than normal. It's the same way in which 1080p doesn't make a difference compared to 720p when you're too close to the screen. You're basically paying a lot of extra money for no gains, unless you plan on moving farther from the television.
I'll have to disagree. I can clearly see the difference between 720p and 1080p and my vision isn't even that good. Granted, I am talking from experience with monitors, but that shouldn't be a difference. (I dont really have a TV in my house, I never use it..)