The smith machine is just another tool.
You're not a pussy for using it. You're not non-functional for using it.
It's a solid piece of equipment that requires a lifter to do different things than with free weights. The added stability and fixed bar path allow you to "zone in" on a particular muscle group and keep pounding a particular angle. Don't abuse the machine's stability to move weight in an uncontrolled fashion.
You don't see my hips shoot back as I come back up. I keep everything in line and crank through the range of motion with precision and focus. The bar does exactly what I want it to do. At no point do I give up control for weight.
As always the only thing that changes as I fatigue is the speed of each rep. Range of motion, pauses in the hole, eccentric speed stay the same.
My body has no other choice but to grow if I continue to add weight over time while keeping execution strict like this. Chance of injury: virtually zero.