bands and chains are great fr the raw dogs. Just keep stuff honest. What I mean by that is something like this example. Say you can bench 225 x 5 for a few sets. By adding a set of 5/8" chains to each side, you’ll be doing roughly 25# extra ( don’t sweat the chain weight, just log 1 chain, 2 chains etc, this is per side btw) now do the same 225 x 5 for a few sets. the overload will work your tri’s, teach you to push hard all the way to lock out, all the benefits you read about. One can even drop the bar weight a tad. Say 205 and add 2-3 sets of chains. This will give your chest / shoulders a break, especially if you have beat up old shoulder like me BUT keep the bar weight up. This leads me to my next example.
What you DON’T want to do is be like a guy I know. Using the same 225 for an example this dude would load 135 on the bar and an ass load of chains. Bar weight would be around or just over the 225 at the top & he reps the shit out of it and thinks he’s kicking ass. He is exercising with chains, not using chains as a tool and certainly not as they are intended on being used. This is not to be confused as “Dynamic” benching, where that application would be appropriate. This cat uses light bar and tons of chains as a max effort type movement.