Not necessarly true!!, I have replaced the LCD only, but taking off the damaged LCD from the good digitiser is really hard!!!
1. Put a screen protector on the original Digitiser!!!!! ( can be a second hand one, just wash it with soap, shake off the excess water, the remainig water will squeegie out, you need this to protect the Digitiser!!!)
2. Use a Hair Dryer to heat up entier screen front side, this makes the glue soft.
3.You have a small window of time to pry off the LCD< you will have to break it, so don't try to worry, it will smash up into tiny pieces and statter, so this is why you the screen protector on the front side, use a guitar pick to slowly pry away the old LCD smashing it up as you go, keep the Digitiser FLAT or you will break it!! try to do 1/8 area at a time
4. re heat!!! do step 3 again , over and over till you have it off.
5. Clean up the digitiser with a broken pice of LCD sticky side, then finall claen with Alcohol.
6 install your Generic LCD to middle board and carefully place digitiser frame around it, and install the 7 screws.
7. make sure the LCD is dust & smudge Free, and place the Digitiser over, if it looks good and clean put the double side tape on Digitiser frame and final Fit the digitiser Glass.
Once it is all together only an Expert can tell the difference!!
People wont worry, as this repair is half the cost, just give them 2 options for repair, and 2 prices for fused or non fused repairs, hope this helps,!!
P.S> if you want a faster cheaper way just buy the Digitiser and LCD seperate and install to orginal Digitiser fram, carefull with home button Ribbon it breaks easy, so have a few spare just n case.