the downside is that if u are not able to get 600 BA tier point, you wont even get any lounge access as you would have when you fly CX as a CX silver. if you are willing to spend your own money, it is fairly easy to rack up tier point by flying cheap business class ticket. This is how many 70s years old parents, and 3 years niece able to obtain 2500 BA tier points in their first year of membership basing in HK.

i estimate that the 3 years old obtain BA gold for 25000hkd via discount long haul business class ticket and child discount. pretty sweet, i would say. (no mileage running, all vacation)