From Dark and Darker Wiki
< Golden Chest-Inferno and Ice Abyss
It's interesting that the chance for a legendary gem is the same between Highroller and Normals specifically for Inferno & Ice Abys. Pretty Neat. So the only reason to go into high roller is so that Crypts chests drop legendary gems otherwise you can wait for inferno and have no advantage for gems (besides pile if you kill the boss).