I formerly worked at Uber. I’m surprised that Bolt blocks the web app from working. Uber also built a web app which is incredibly lightweight - here’s a summary on how it was built [1]. It’s a life saver especially if e.g. at an airport and you pay for data over roaming. Uber doesn’t exactly advertise m.uber.com, but there’s no blocking of it.
My suspect is that Bold wants you to use their app as they can eg send push notifications, and gather more metadata from users - some of which can be used for eg more signal on determining if a request might be fraudulent.