I've only seen a video of this and I admit this sounds as a reasonable response.
I've also once seen an other video where one changed "what you take/spend" of resources (spend or gain money/elixer/dark elixer from the mine and elixer thingy).
It was done the same way by editing the resource parameter in the"buildings" file but it, too, is encrypted now.
Strangely, the game didn't refresh in that video and all was going well.
If somebody could do that again, maybe it's possible to change the parameter to gems and see what happens???
Or even use it as it is!