[neetdavid]

People use them as another tool for finding glitches and exploring the possibility space of the game's systems. They're basically using debugging tools and in some cases even looking at memory allocations etc.

As for full length tool assisted runs, I just find them to be a fascinating new lens to examine these games under. It's cool (depending on who you ask...) to see what the game looks like when another computer program is piloting it perfectly towards the goal of 'finish as fast as possible'