People have differing opinions.
In my opinion, Smith is fine for some things. I Squat on it, because trust me, squatting alone Freebar, and not necessarily having a spotter, is not a risk I'd be prepared to take.
As for Benching, some do it, when there is no other option, as it's safer than Benching with an Olympic Bar, and no spotter.
You need to do what you feel is best. I don't feel there is a necessary right or wrong with a Smith. I've read plenty of people saying Smith is fine in some instances, and others not so positive.