Using fake money gambling application might be a good platform to curb gambling addiction but it would fail if there is no will power or determination to quit. Like you rightly pointed out mate that these application was mainly designed to improve gambling skills and experience. It might serve as a tool of increasing the addiction. After using the application to master some skills, most addicts might want to apply those skills to real gambling. Its just like advising a sex addict to curb his sexual drive by watching pornography.
It is true. if a gambling addict wants to get rid of his addiction to gambling, the important and main point must come from the person's determination and will (intention). because if there is no intention to stop then an addict will not listen to suggestions and criticism from anyone, even family. because that's how I felt in the past. even I myself have a strong determination and intention to quit gambling after experiencing a big loss that almost made my fortune almost bankrupt. After I realized and there was an intention to stop then I looked for suggestions and solutions to stop starting from listening to family suggestions.
and regarding the app the OP mentioned about playing fake gambling with fake money I don't think it would be very effective either. because as you said this will only make the urge to gamble stronger. although it might work the OP's way. but I think the comparison is very far between what works and what doesn't work.