How can you speak for what most of "us" use? Each tactical option has its own advantages/disadvantages.
Just because you don't fully understand it or have had poor experiences by playing it incorrectly, doesn't mean that the whole system is crap.
Each substitution option allows you to assign how much control you want to give the coach. Ranging from 'Strictly Follow Depth Chart' (low control) to "Let coach decide" (a lot of control).
Needless to say, if you have Lebron as a bench player with "Let coach decide", the coach will still give him huge minutes and might even start him because at the end of the day, the Coach wants to try win the game.