Burning tokens has no long term value at all. Lets say you as a investor loose half of your tokens because they get burned. Because of that the price rises and may spike a bit because people who didnt knew about the token burn would think it is a naturally rise of the value and would get in. So all you would do is fooling people who are not involved in the project. But after some time the price would settle to a proportional value of the price right now.
Since Monetha is a serious company and not interested in pump and dumps, it wouldnt make any sense for them.

To answer your question about the tokens out of circulation you should read their whitepaper. In their you can see how they got distributet. They belong to monetha and are locked for a year from the moment of the ico.