Both are difficult in my opinion, where self-control to not continue playing is very difficult, where when chasing long-term wins I personally sometimes forget the time and how much money I have wasted, and what's worse is that the wins are sometimes not comparable to what has been spent.
You're right, both self control and maintaining long term wins are hard, but I think a place like rollspace where you play to earn and you play against fellow people, will help to maintain self control to a certain extent and also help with maintaining long term profits