I have had opponents switch on me in game, albeit much later in game. One more argument for Bulldoze is that because it is a single turn move instead of a double turn move, you only have to get through something like paralysis one time to get a hit in. With dig, you have two turns for paralysis to take effect or you have to burn twice as many turns to heal. Even though garchomp is a ground type, it can still receive paralysis through moves such as body slam, bounce, or force palm. You also are twice as susceptible to accuracy reducers.
The only positives that dig has over bulldoze is that it has base 80 attack and might play a minor role in getting out of an occasional cave.
I don’t think it’s enough to say it’s a better choice than bulldoze, but that’s just my opinion.