Simply holding them would create the same effect, and actually there needs to be enough Bitcoin available for the price to go up. If there wasn't enough Bitcoins it could actually cause the price to go down because people wouldn't be able to use them and they would move to something else.
About holding them would create the same effect instead off burn them is true, but the fact that price to go down because people wouldn't be able to use them and they would move to something else is still arguable, even in the case that they burn 10% of entire supply, even though the unit minimum is the "satoshi" it can still be divided as many times as necessary, since there are many subunits which would not represent a big problem in theory, but it would be illogical to think burn units, to create subunits later, apart from the problems in the credibility that this would affect more than anything else, that is, to be altering the code only for things that can be avoided, in short the idea of burning 10% of supply seems to make no sense.