If you can spin a crank at high rpm a Biopace will not make any difference and may even improve your pedal stroke a little... like Sheldon I have used Biopace on FG and SS bikes and found that it worked quite well and also run a Biopace triple on my Extrabike as it has benefits at the low end for maintaining cadence under higher loads.
It is a sound design.
As for tossing out the cranks that came with them... my Kuwahara Cascade came with Biopace rings mated to a Deore cold forged crank which I continue to use to this day and am looking at re-installing Biopace rings since I have a bunch of them, many are NOS.
With one good leg I find that my right leg does more work and my right knee is more prone to being strained and stressed under harder efforts but have been riding my Biopace equipped cargo bike with a 28/38/48 and an 11-30 cassette and never found that I needed a lower gear.
As I was swapping the old 11-30 out today I switched to an 11-34 and lowered the gear a little... these BP rings are running on another Deore crank and I do not part with these easily.
Biopace can be magical for people with knee problems.