What is it about the MacRumors forums where the problem gets solved, and then other people still reply without having taken into account that new piece of information? It's like people just read the original post and immediately hit reply without thinking it useful to read the rest of the replies first.
Sorry for the rant. Now on to some useful comments...
You two may be surprised. A lot of us techy people want the new iPhone 6's because we like the idea that higher resolution means seeing more things on the screen, but I know of three people in my family who want these bigger screened phones because of their failing eyesight. I set up my father's new iPhone 6 yesterday, and he wanted the Zoomed mode. Once I can score a 6+, I will be giving my 6 to my wife and she wants to use the Zoomed mode, too. And I'm pretty sure that my older brother wants to also use that mode.
To address the issue of "graininess" when using Zoomed mode and viewing this website...I'm not exactly sure what it is you're looking at and seeing, but know that scaling the resolution from the iPhone 6's native resolution to a pseudo-iPhone 5 resolution is not as simple as multiplying the pixels times a whole number. The home screen should look sharp because most icons should be using vector graphics, and the fonts are vector fonts that are scalable as well.
Any sort of bitmap graphic that a website or app uses will need to get scaled up in an imperfect manner that could result in things not looking as sharp. Most of the ads here (among other things) would fall into that category. I just tested it out, and it the ads don't look blocky, they look soft. I suspect iOS scales them up but also applies some sort of softening filter on them.
I don't like the new flat design that Jony Ive ushered in, but a lot of the skeumorphism of the earlier iOS versions were the result of a lot of bitmapped graphics. I suspect that a big reason for the shift to the flatter design was to allow for easier support of a variety of screen resolutions.