people with ac joint issues benefit greatly from a smith machine while still being able to lift near max effort weight without worrying about joint stability and i could introduce you to dozens of monsters who swear by the smith machine for bbing purposes. people who are into bbing for the long haul recognize the importance of a smith machine. your joints wont last forever in the 5 x 5, there is a point of diminishing returns.
and dont assume you know what optimal training is. not everyone has the same goals.
Smith machine puts your body at unnatural angles, with unnatural bar movement. ON top of that you don't use any stabilizer muscles as the smith machine takes care of that for you. So when you go to lift something in a similar movement in real life, the stabilizers are weak and that is when injury happens.
I don't care who uses the smith machine, it is an injury waiting to happen. Strong/ big muscles and weak stabilizers = injury.
As far as optimal training, adding strength and size allowing the body to grow as a whole while doing it in the most efficient way is optimal training.
The useless bb split he posted is not optimal training for anyone new to lifting, or even people that have been lifting for years.
Most successful body builders have a power lifting, or similar strength training background. they have spent years on core lifts, building mass and getting stronger. They already have the size they need to compete. They may then turn to a BB type routine to focus on specific areas that they need to please the judges, but this is after putting on size with core lifts. They didn't get there by doing BB splits, if they did, they spent thousands, on top of thousands on juice.
For a new lifter to go out and try a program that is for someone that already has size and just wants to focus on specific areas is far form optimal for that person. Optimal training for a new lifter is core lifts, adding weight to the bar, with planned progression. It doesn't matter if the goal is to add some muscle and loose BF (get ripped), or add size, or just get fucking strong, the training is the same, diet is the variable.
So ya, I know what optimal training is.