Chances are that this scheme will be used to implement your language's dynamic array (or the standard library for that). So unless many people tend to use different dynamic array implementations, or fiddle with their regrowth-factor, then it is indeed being used as a "silver bullet".
That is one thing, and a different thing is recommending that people go through all their allocations ever and just make them all grow exponentially on a x2 rate without much more consideration to what was expected in each case.
If someone is not critically reasoning about what is needed in their specific case, exponential growth is going to give far better results on average than constant growth.
If someone is critically reasoning about their allocations, then presumably they'll be able to pick up the (fairly rare) cases where exponential growth is sufficiently detrimental to matter.
