Of course there are margins and studies that cross them.
Nevertheless, you don't get to understand biophysics without background in both. Not relevant in the context of an IDesigner who is not constrained by patterns that appear in biological studies related to evolution.
That's self-evident.
But, I'd guess that biophysicists are not merely people who have a double major in physics and biology. They are people who cultivate the interaction (cross-pollination?) of the fields.