The absolute sweet spot of BAEC, so long as you understand that, instead of a free flight program, you will be traveling in business class for coach-class fares. It took me awhile to get this, but I now look for WT+ sales (held regularly enough), use the 10% discount provided by the Chase BA Visa card on all fares to buy tickets that cost roughly what I'd expect to pay for a coach seat, upgrade the TATL segments at 10K each, and earn almost enough between the Avios earned for the miles flown and my charge to Visa to offset the Avios used. And, with the Multitrip Multiplier bonus currently on, to bank a few extra Avios as well.

I have found it really instructive to do side-by-side bookings with a CW upgrade from WT+ and a straight CW redemption. JFK-LHR-JFK is 20K Avios plus roughly $1000 (during the current sale) for the upgrade with approximately 12K Avios earned (assuming payment made by the Chase BA) but 80K plus nearly $700 for the redemption--with no Avios earned except the 2.5 Avios/dollar earned if you pay with the Chase card.

If finances don't allow this kind of use of Avios and free/cheap flights are an imperative, the values you've found are also a great way to use Avios. But, Sixth Freedom has hit the nail on the head as to the best way to use Avios while also continuing to earn Avios. I have a very special trip set up for two years from now, and I may fly F on a redemption then, but in the meantime, I'll continue to take several TATLs per year in CW while keeping my Avios tank topped up.