snapdeal has been integrating a lot of third party apps in their own app. i have no idea why other companies think it is a great idea. i guess they understand that through such a collaboration, they get a readymade customer base of millions which they would not get otherwise. but they also become dependent upon snapdeal for a large part of their business!
uber of course is different. it is quite large on its own. everyone knows about it. pretty much everyone has an account on it.
Uber has a deal with BookMyShow. But BMS makes sense as the app provides you with an option to book a cab for the movie/event you booked the ticket for. Snapdeal has zero logical connectivity with Uber.