It will still benefit those gamblers who are abusing their credit cards for gambling but they will surely still find another mode of the transaction just to pursue playing.
But at the very least, UK government imposing a regulation on using credit cards for gambling will still help them in the long run. Most gamblers, including cryptocurrency gamblers, lose money all the time. They try to make up for their losses by buying more coins to hope for a shot at winning. Which most of the time, as we all know, ends up in vain because of how the gambling industry works.
As long as crypto gambling is legal in their country, no one could stop players to gamble because there are still alternative ways except for credit cards.
Now with imposing this ban on credit cards for gambling, this ensures that whatever happens, even if these people make up for their losses by betting again. They wouldn't be in debt with the bank they are in. Further giving them the chances to not be homeless someday. I think despite the negative remarks it receives, it still a good move in UK's end. It shows that they care for their people and wouldn't want them to be in debt.