I find machines hyperfocus the training on specific muscles, but take away most need for stabilization. They can also cause RSI-like effects by constraining you to one and only one movement path.
With barbells (or dumbells, or kettlebells, etc.) you have to not only lift the weight but also balance/stabilize it, that recruits and strenthens a lot more small muscles along with the major muscle area you're training.
Machines and dumbbells initially when I injured my arm (it was a repetitive use thing and not a trauma), and then after a long break and trying to let it heal, I switched to barbell for most things, along with a pressing machine (because I don't have somebody to spot me for bench press) and a pulldown machine.
I find machines hyperfocus the training on specific muscles, but take away most need for stabilization. They can also cause RSI-like effects by constraining you to one and only one movement path.
With barbells (or dumbells, or kettlebells, etc.) you have to not only lift the weight but also balance/stabilize it, that recruits and strenthens a lot more small muscles along with the major muscle area you're training.