The Sarlacc Pit is a deep pit with teeth covering the inside of it. What we're looking at is a deep pit with teeth covering it. Somehow by making a fake Sarlacc Pit, you end up making something nearly as deadly as a real Sarlacc Pit. That's not true for the other things in Star Wars, like an AT-AT or a lightsaber. If you fell into this fake Sarlacc Pit, you'll get just as hurt as if it were real. The only upside is that you wouldn't be digested for a thousand years. That's definitely a plus.
We're so used to seeing CGI creations that it's hard to believe that some of the things we see in movies actually exist. You could reach out and touch them if you were on set, or in this case, fall into them and break both of your legs.