I do agree with the part on Bounties and airdrops, I am not that convinced on the exchange part. While it is formally true that exhcnages don't add value but allow for exchange of value, we have to admit that in the current crypto scene being added to several exchanges (where some are better than others) gives coin credibility, popularity and a general belief that the coin is worth something. So as a matter of fact it adds value, moreover if your coin has value but there are no ways to buy it (exchanges) this value will never be reflected in a price increase (price that is by the way calculated as the average between exhcanges that list the coin)