That's a definite it depends :) In the case of Uber, all those didn't help acquiring me as a customer. I wasn't even aware of the existence of any coupons, ref

That's a definite it depends :) In the case of Uber, all those didn't help acquiring me as a customer. I wasn't even aware of the existence of any coupons, referrals and stuff. I installed it because clicking a button in an app is much easier than calling for a taxi on voice AND explaining where exactly you are. In other cases though, they help. If you don't have a free trial or free tier and don't have an unique offering suited to me, how would I know if I want your product? As a small piece of anecdata, I would have never subscribed to GeForce Now if they hadn't let me try it for as long as I wanted in 30 minute sessions. Coupons are a well known form of discounting for customers who have more time than money. Referrals may be useful if your product needs to achieve critical mass. Etc etc, I'm no professional marketer.