Twitter lost 456 million dollars in 2016 [1] and I don't remember them ever being profitable so i don't know how those people are wrong.
For start ups it can turn out cheaper as the compensation will be lower in stocks if the company doesn't perform well. From a shareholder perspective it's compensation and shouldn't be treated differently. Excluding it from costs is dangerous as it gives the impression that it's optional costs when in reality, you need to pay the stock compensation to retain talent.
Also, twitter is a platform that has exclusivity. Uber is easily replaceable with Lyft or a taxi service's app. Just because a friend is using Uber doesn't mean I have to. The same doesn't apply to twitter, the platform is the value. This is what kept and keeps twitter afloat, Uber on the other hand paved the way for a shift in the way we consume cars as a service.
But who knows maybe Uber will stop being the dominate taxi / self-driving car company globally over the next decade and mess it all up. Or not... but I doubt this large expenditure was done without foresight. The question is whether they can dominate for years to come in a high-growth industry, which it seems likely given the wide gap between them and the competition.