Both are really not easy when you have already become an addict but still controlling it is more more easier than quitting it forever. To quit gambling takes a while lot of time and just a little small mistake can alter everything and take you back to gambling in my opinion. That's why my advice is always to avoid getting addicted by every means possible, discipline yourself that way it will be easier to control your gambling habit and not get addicted.

Absolute abstinence is more effective for people struggling with gambling because when you gamble even with moderation you can easily lose control leading you to chase after your loses and resulting in more financial loss which will eventually lead to addiction.