If BiaB was just a fun simple and easy-to-use program I don't think it would be used by so many musicians all over the world. Yes, to fully use the program to it's max capability and push the envelope you will have to dig in and study hard and get a lot of BiaB time on your clock. I don't think that most users will use the program to that extend (I sure don't).

It is however pretty easy for one to:
A: type in some chords.
B: click play
C: click stop
D: Change the style (finding the right style is another thing)
E: Change the tempo
F: Change the key

With these simple steps you can build a simple song. You actually started using the program.
Later on you'll want to add rests, shots etc. Simply look it up and use it; Slowly build your knowledge step by step by adding a little function one at a time.

No BiaB is NOT an easy program to learn.
Yes, you can start using BiaB real fast, almost without even reading the manual.