I agree on the resale issue, hardly anybody likes bananas (I do, however). Also, I agree on the extra connection, especially if this adaptor is mostly brass (which I bet it is).
Bananas vs. Spades
I bought some older Audioquest cables (Crystal) for shotgun biwire from McCormack DNA 0.5 dlx to Vandersteen 2cis. These cables are big and heavy. I am sending them to AQ to be terminated and I have two options for the speaker end (Vandys have factor bananas at about 30" off floor). Could use bananas as intended with supports to prevent weight of wire from damaging speaker termination or (worse) the banana jacks on the speakers. AQ technician recommends using spades and then a spade to banana adaptor that fits up close to the speaker and allows the wire's weight to pull straight down, with weight much closer to the fulcrum (so to speak). What do you all think? I fear a loss of sound quality by using two connections, but there is also an advantage in having spades on both ends for re-use or re-sale. Any advice appreciated. Thanks.