I have to agree with Mr. 6897. Too many variables to know what is responsible for the sound improvement. As he said, "if you like it, it was successful! Congratulations!!!".
If you prefer the convenience of bananas, next time try a set of low-mass BFA style banana plugs. They have excellent contact area and tend to fit very snugly vs. the spring type of banana plug. They also put constant force on the inside of the binding post and do not cause the binding nut to loosen. The low-mass BFA banana plugs are now my favorite type of speaker connection by a wide margin. They also work with certain amps that were designed for the UK market that have a pin in the middle of the binding post. Standard spring type bananas will not work with those amps. Arcam Alpha 10 is an example of one of those types of amps where BFA style bananas work, but standard spring type bananas won't.