What to do with the silver portion is another topic of discussion, but burning away will not make any significant difference to the value of XEM in the long term for sure.
If we look at an optimistic long term value of 15c, that 200m is only a drop in the ocean. Won't make any difference that will make it go down by even 20%. If it does, blame it on market volatility.
And by the time it reaches 15c many of you will be quite rich, especially those who believe in this project and have been patiently collecting. They deserve it anyway. Likewise, for those who are working hard to put value in the project.
As far as I know, silver coins were planned for early adopters. It's ok buy why not giving the coins an additional marketing function and sell it outside the NEM-circle to achieve more publicity for NEM.
(my idea: 1ounce .999 silver, 24k goldplated, for stakeholders, limited and unplated silver version for public sales???)
other marketing silver coin ideas welcome