Is there anything special about ‘key man insurance’ for a business other
than the fact that it is a life insurance policy that names a corporation as
a beneficiary?

If I understand the purpose of the proceeds correctly it would fund a
buy/sell agreement. Unless you want to be partners with your partner’s
spouse or children, that’s what’s special. It can be used to buy out the
family of the partner so the closely held company can keep running and not
put everyone out of work if the key man dies. Of course you have to have an
annual meeting and set a value on the company every year at least so the
insurance would cover that.