An interesting dilemma. When asking the original question I had snapshot in mind as a method of Blacknet distribution, but whether it is snapshot or burning may be not that important in the considerations below.

If 1 blackcoin = 1 blacknet or 1 ercoin, then investors will have an opportunity to make a decision of how to divide funds between Ercoin and Blacknet. If 1 blackcoin = 1 blacknet and 1 ercoin, then investment preferences in this regard will not be reflected in the initial distribution and there will likely be a lot of trading after the launches to achieve state from the former case.

In the latter case, the fact that obtaining Ercoin via burning will also mean obtaining Blacknet and vice versa may mean that more people in total will hold both currencies, which may result in greater adoption. On the other hand, if people are not allowed to choose between the two currencies, then it may form an incentive to not purchase BlackCoin at all, wait until the launch of the currency they’re interested in and purchase it on an exchange. In particular it may therefore result in a lower value of BLK burnt/snapshotted and therefore lower perceived value of both currencies.

“Merged burning” (allowing the same burned BLKs to participate both in Blacknet and Ercoin distribution) may form an interesting marketing opportunity, but so may another alternatives.

Weighing the pros and cons above, I’m currently leaning toward 1 blackcoin = 1 blacknet or 1 ercoin.