I found a free iMac G5 on Craigslist which didn't turn on. I needed to take off the screen, and the only tool that would fit into the opening was a thin T10 Torx driver. I got the security bit driver because I already own a whole set of Torx drivers, but none of them were thin enough, and I figured I might need the security feature in the future.
The driver fit in the spot needed, and I took the whole thing apart. Still haven't swapped out the power supply, which is the whole reason I took it apart, but since it was a free project I am not in a rush.
Don't try to use a "security bit" set for your electric drill to get in there, just use the right tool and it's infinitely easier.