I was wondering about what will happen to the test mastercoins... will they be deleted when the protocol is working? Otherwise, it could be that they become valuable as well.
Testnet bitcoins aren't valuable. Everyone knows test mastercoins should not be used for serious purposes, and nobody is promoting their use for serious purposes, so nobody will use them for serious purposes and they will have no value.
Testnet bitcoins are running on a separate block chain. Test mastercoins however are on the same block chain as regular mastercoins. And if they basically can do the same things as normal mastercoins, why shouldn't they be used and gain in value?
If testnet was merged mined against mainnet, tesetnet bitcoins still wouldn't have value. When something is branded as "testing" the
Schelling point is that it will be used for testing (especially when it offers no advantage over something branded as "real").
If test mastercoins would so easily have value, it will be trivial to generate 1000000 different Mastercoin "flavors", each following the same protocol but with a different "version byte" (or whatever there is there). If all flavors will have equal value then mastercoins have no chance to have value to begin with. But if not then mastercoins will have a huge advantage over test mastercoins by virtue of being intended for actual use.
But test mastercoins were released together with real mastercoins simultaneously. As far as I understand, you can do the same thing with test coins as with real coins. So, if there will be an exchange trading them in the future, they WILL be useful, and you can trade them back to bitcoins or whatever and buy something with it.
There are so many other cryptocurrencies with hardly any innovation in them, but still they have some value, because you can exchange them with other currencies.
I just wanted to mention this possibility, because ultimately, test coins might lower the value of real coins because of more supply. So it might be good to destroy them at some point, before it's too late. And of course let people know early enough about that action. I think this helps, because people can actually treat them as test coins and therefore also 'waste' them for testing purpuses.