The question is why they haven't used stablecoins in this way until now. It's very easy to prepare the infrastructure. Legal procedures shouldn't be difficult to handle either. There is no obstacle to do this, but these companies cannot keep up with the speed of technology. It makes life easier for them to get paid with stablecoins, but it has no effect on Bitcoin. It would be nice if they accepted Bitcoin. By the way, Uber doesn't even exist in my country, the government banned them because of the taxi lobby. It's very strange that there are such differences in the world according to the region you live in.
Uber is a global brand and you can wonder why they are just realizing that crypto and stable coins have no barriers except in countries where they are banned. They should speed up the process so that passengers will have options if they don't want to pay fares in their traditional currencies, crypto adoption is increasing and their business should move along with the trend. When they start with stable coins I believe that the next step should be to accept Bitcoin because it is the most popular cryptocurrency and Bitcoin holders who wants to spend their coins can patronize Uber for their movements.