We have used unipolar with direction selection on every application so far. We have not avoided bipolar, we just have not installed one.
Our applications are moving product (ore, brine, dry product) from here to there.
The conveyors that do reverse, do so in specific situations. A separate signal for reverse is seen as a positive.
We have screw conveyors that move product in 2 directions normally. They coast to a stop forward before allowing reverse, coast to a stop reverse before allowing forward. Again, uni-polar is seen as a positive.
We have a rotary plow that allows for reverse when jammed. It is bi-polar and we have actually wired it to a uni-polar output and used an output to drive a DPDT relay ... to make it uni-polar forward or unipolar reverse.