Sure, but if you want to practice and tighten your shit, especially as far as double bass and blast beats are concerned, you need to practice with a metronome. Death metal (or extreme metal in general) demands precision, especially during the recording process. It makes everything all that much tighter.
Not to mention, there are some great stamina excersizes that use a metronome.
Nobody has perfect tempo and that's why metronomes can be helpful. Practice with one for a week and your "naturally awesome rhythm" will improve, guarantee.