Possibly because I work with vouchers and as a service provider its a pain to work with. When it comes to a mass discount voucher company, especially like one like Groupon, I do everything I can to avoid it. Because those kind of companies fleece and cheat both the provider and the consumer. As for discount vouchers that come from a company or gift vouchers, I'm very wary of them, but I am willing to try them out if their Ts&Cs are not too oppressive to the parties involved.
By the way, UBER is a high class taxi service with screened drivers and luxury cars, they only come on demand (via ordering a pick-up on the mobile app) and are cheaper than other taxi cabs. They are a fad that has taken the world by storm and are in top cities all over the place.
To the wonderful sponsors, thank you SO much, I really appreciate the gifts.