You no longer need to try and describe a sound or a leak, you can capture it on your phone and show it to the repair person. At the other end, if the wrencher says something's wrong with your car, you can ask to see photo and video proof of the issue. The caveat here is that the repair shop has to have the latest version of the app that allows the multimedia exchange – it isn't a customer controlled feature.
Of course, you could exchange photos and videos without an app, but Openbay is an entire suite of services built around car repair. Dealers, franchises, independent shops, and mobile mechanics are all there, with the requisite ratings and reviews, and they respond to service requests with detailed quotes, not merely written estimates. Shops don't pay to be on Openbay, they only get paid after performing repairs, which eliminates shops jockeying for prime positions and is an effort to ensure transactions go smoothly and shops honor their prices.
Taking a page from much larger marketplaces, Openbay guarantees ( click here for the details) every transaction done through the app, and it keeps a record of every repair performed - the modern version of that manila folder full of receipts. The app is iOS and web-only for now, but an Android version is coming. Until autonomous robots get about fixing our autonomous cars, this could be a worthy option.