I can simply say that if the benefits were not worth, Github and most companies doing projects there should have closed years ago 
Opinions are great because everyone may have theirs; which is fine. Facts are what we can see with data, measure and bring up as clear examples. The greatest revolution that internet brought has been the ability for people to collaborate on a project together. The specs may be guarded by a committee or standard; the commits gated by a set of individuals; the project may be for free or for profit; but the fact is that there is an advantage in most cases.
The example of a case for not going that way is when you don’t have enough capable people enough to contribute; which means you have to babysit a bunch of wannabe programmers whit no ability or knowledge. In that case,yes; it is not worth it.