I know the underlying call, but I always see the redirect symbols as indicating that "everything" on the big side of the operator fits into a small bit of what is on the small side of the operator. Like a funnel for data. I don't know the origin, but I'm believing my fiction is right regardless. It makes <(...) make intuitive sense.

The comment about "why not &2>&1" is probably the best one on the page, with the answer essentially being that it would complicate the parser too much / add an unnecessary byte to scripts.