It is quite relevant if you work with public entities - schools, cities, etc. There are people out there who test government sites to be sure they are compliant and report it to the DOJ when they find failures. And the folks at the DOJ will call you to discuss it. Those calls were surprisingly pleasant and helpful, at least in those days (I haven't done that work in 5 years), but if you think you won't get called out on it in public industries, you'd be mistaken.

It is not necessarily relevant if you only work with private individuals and entities.

But it also isn't that much of a burden. So my take on it is just do it and then it never is a problem.