What is the best way to avoid expensive tax to redeem Avios?

When I try to upgrade from World Traveler Plus to Club world, which is from SFO to HEA, it will cost 30k Avios plus $580 one way. If you want to upgrade round ticket, it will be double.
If I upgrade with money, it will be $650 total for one way. This simply doesn't make sense to me of earning avios.
I recently upgraded from economy to business class with other airline and with different mileage program, I only spent the accumulated mileage without tax.
I don't find any benefit for BA executive club. Please share your experience or any opinions.