Holes in plastic require a negative rake cutting edge.
Yes the step drill works but it still is not the best tool for the job.
Just as the chop saw uses a negative rake so as not to grab,,, so does the drill designed for drilling plastic. The negative rake will not grab and pull the drill into the plastic,, which avoids the cracks and breaks.
Same goes for cutting acrylic with a power saw. Using a panel blade set backwards leaves a good edge from which to work without causing mini cracks along the cut edge.
A negative rake can be set on any drill using a grind wheel. It doesn't take much. Just about 7 degrees negative works.