In my personal opinion, whilst a blank line-up + LCD can indeed be powerful, setting a proper line-up has it's advantages as well. Mainly the fact that with a blank line-up, the coaching AI will quite often put a player in a position on the court where their best skills are somewhat wasted. I remember one U21 game in season 26 where Mick did the blank line-up LCD, and Hampshire got played mostly at SF when any rational manager would instead play him at PG to take advantage of his 16 Passing skill.
There have also been times where I have played the blank line-up LCD and seen some of my better players get left out of the starting five altogether, in favour of inferior counterparts. Usually the minutes balance out well in the end, but I would think that it would be only rational to have your best possible line-up out there for the opening tip...