Why are face masks mandatory when travelling in an Uber?

Uber drivers don't want to catch Covid19 from their customers. 

Technically an Uber is a workplace, if there was any real chance of catching the virus they would have to shut down their business and lose a lot of money, they are just being cautious. Since you may be sitting in the same seat as a bunch of random strangers had sat in the past hour it just kind of makes sense that the risk would be higher than average.