I can see that HDRI's are nice for rendering certain materials but are they necessary for everything we do in Bryce?

I decided to see what would happen if I HDRI'd a seascape and just used the normal bryce lighting on the same seascape. I used the beach hdri  and rendered in superfine which took 37 minutes.

Then I removed the HDRI and readjusted the light in a second rendering of the same scene.I used superfine rendering and it took 4.06 minutes to render.
Maybe I don't have to rely on HDRI every time?