that was my same thought i had too, thats all i did was just clean the digitizer very good, but some people swear that the glue makes a difference look wise, i would have to compare but to me even without the glue on the digitizer the screen looked just as vibrant as OEM look.
I got the optical glue and it doesn't cover the whole screen. They sent the wrong size and I used it anyway. It covers all but ~1" on the bottom and ~1/4" on the top. There is a big quality difference. I guess you could say the images aren't as vivid.
I'll try to take a picture to demonstrate.
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