But it isn't efficient. Its so inefficient that the staff have been reduced to using a marker on the screen. Its not a failure of management communication or proper training. It's a failure of the product.

That could be the case or it could also be the case that the head waiter never took the time to learn and has refused to change his ways. Hard to say from just one data point. The same system could be successfully used in thousands of other restaurants.

You have no facts to prove your claim. You don't know whether or not a) the management clearly communicated to the staff; b) the new system is actually more efficient; c) the headwaiter isn't actually the manager that put the system there in the first place; d) this event happened "in the long run", after working with the system as it should after which stakeholders decided that it's actually not efficient, etc etc.

You can blame management and bad communication all you want but the fact is that what seems rational and efficient for some people (management) is irrational and inefficient for others (the person actually doing the work).