Sure, machines aren't perfect, and they railroad your form, but it's better than nothing. I train on machines, _and_ with free weight, _and_ doing bodyweight / crossfit stuff. They all have their place.
There's no way I'd try to pull the rep max on a free barbell that I would on a smith machine, but it says nothing about how effective one or the other is.
It's like the whole internet self defense huff. A billion words written on the technicalities of all the different martial arts but most fights are won by punching the other guy repeatedly hard enough to stop him hitting you. Sure it's not perfect, but its taking action and it gets results.