OK, I'll give that a try.

I guess the value of that, relative to the alternative strategy of just using the mileage accrual FF#, and showing the other card to get into the lounge, is receipt of the other Star Gold benefits, which look like mostly higher priority for check-in, boarding, standby, etc., and extra baggage allowance. Perhaps SQ will also be nicer to us in other ways because of status, although my experience has been that SQ will be nicer to me as a nobody than UA will be to me as a 1K