It looks like Arbitrary will sample integers from an uniform distribution. For property based testing you often would like to have a bias towards "interesting" values that might trigger special cases, like -1, 0 and 1.
E.g. if you had "max_speed_kph: Option", your tests might never check what happens if max_speed_kph is 0.
One also may bias values to be similar (or equal) to other recently generated values. This was a trick used in the compiler tester yarpgen, where it was useful in testing optimization of bitwise operators on integers.
https://github.com/intel/yarpgen
https://github.com/intel/yarpgen/blob/main/papers/yarpgen-oo...
(see "Policies for constants", page 196:8.)