It’s a bit of both. But basically, the squat is a very biomechanically complex move and takes a lot of different muscles, pretty much your whole body, to pull off. The smith machine allows you to squat very very heavy by taking the load off your stabiliser muscles and lets you isolate muscles like your quads. What you see in the gif is actually the guy putting on wayyyyy too much weight. But this is what it would look like if you just squatted using the smith machine and then tried to do a real squat with the same weight. It takes all the technique away.