Charlie,
Scaler is a wonderfully written piece of software and something is telling me that you have not tried it, so I feel you are arguing blindly.

For me music is more about "being creative" rather than as you said: "accomplish the task"

And just as you said it, chord builder of BIAB is about "accomplish the task"...
were Scaler is a tool focused more on creativity, learning process, ease of use, exploration, fast, elegant, etc. I found an awkward but working way to have both programs open, so lucky me.