Quality scanning is used to determine the quality of burns on different media and at different speeds. Most of us use it to determine the variations between media batches, the possibility of burning different media brands, and to find the best burn speed. Some drives are very good with +R while others are good at -R. Other uses are to compare the differences between different firmwares, to look for the occasional defective disc, and to determine the benefits of different burn settings on BenQ and Liteon drives.
In the early days of media and burners it was much more necessary to scan because there was so much crap media out there. Nowadays, one can stick to Verbatim and TY and most always get high quality. Some here also use CMC.
LG burners have always done very well on TY of all kinds, although it is not the best on TYG02. Likewise, it is one of the rare burners I have used where it is equally good with all the varieties of Verbatim 16X media, as long as you stick to 8X burn speed. On MCC 03RG20 it is even better than my Pioneer 111 and the latest versions of the LG drives continually improve, unlike NECs.
So, given that you have an LG, and assuming you stick to high quality media, you can get by without quality scanning.