I think they'll work for the reasons Solider and Offroad stated, they'll allow you to handle heavier loads making your actual bench numbers feel lighter right out of the rack. Might not stop you getting stapled at the bottom but that's a different story.
Although I'll disagree with Offroad about the Pin Presses, I think they're dangerous. If you don't get the right groove from the off they can be awkward at best and you may risk injury at worse. I'd much rather take from the rack and bring down to the boards.
Originally Posted by Soldier
I've wondered the same thing. I bet they'd be great for the triceps as well as priming the body to get used to holding heavier weights, but I haven't been able to mess with them because I train alone.
You know even a (suit) belt works for holding the boards in place as long as it's big enough. I've also used old bands and I've even just shoved them under a large baggy jumper.