you're paying another exuberant amount of cash to log an exuberant amount of ICUS hours in a PA31
If you're paying for ICUS, then there is another pilot being paid to be in command of the thing - so you're not taking a job from anyone.
If you are flying ICUS (even if you are paying for it) you are obtaining good, solid, valuable experience -
there is nothing wrong in that transaction.
Indeed, GA is actually helped (as in made safer) by having more experienced pilots.
That situation is completely different if you are paying to take a flying position which is required by the regulations to be filled by a licensed pilot (and should thus be a paid position) - such as an FO seat in a two crew aircraft, or the only pilot on a single crew aircraft.
ex·u·ber·ant /igˈzo͞obərənt/
Adjective:
- Filled with or characterized by a lively energy and excitement.
- Growing luxuriantly or profusely: "exuberant foliage".
ex·or·bi·tant /igˈzôrbitənt/
Adjective:
- (of a price or amount charged) Unreasonably high.