Experiencing something other than the prevailing system
This isn't a tourist attraction or merely a remarkable gimmick. What it does is reverse systemic bias by requiring paying customers to adapt to a system that isn't of their choosing. If you want to eat here, you need to play by a different set of rules.
The original reason for systemic biases is usually benign. "Most people" can't use this, or most people don't look like you or most people won't benefit. Over time, though, the bias in favor of most people becomes more ingrained, and often serves as a barrier to change, reinforcing the power of the dominant group.
I'm well aware that much of what I create is difficult to engage with for people with certain disabilities or cultural backgrounds. And the dynamics of the market often mean that this standard is maintained, usually longer than it needs to be. Signs is a beautiful reminder that we need to actively re-think some of the paradigms about race, gender and disability that we've assumed are normal.
It's extremely unlikely that many other restaurants will hire waiters capable of understanding sign language. For me, the breakthrough here is permitting us, even for a little while, to understand what people who aren't 'most people' or aren't like those in power, have to accept in order to engage with the systems that have been built.