Not quite. While you can straddle a bicycle seat in the same way you straddle a Saddle Seat, the bicycle seat provides little support to the mass of the buttocks. This can be uncomfortable over a long period.

The position of the pelvis is different on a bicycle seat. The pelvis is tilted back, the body is not upright, and the hips are not abducted (not in the spread position). This makes the legs work very hard to stabilize the body.