What do you think?
From the context of the word i think it is basically when people exchange one habit for another. If the new habit is positive, it’s a win-win. But if it is something negative, like trading gambling for excessive online shopping, it's a problem.
It should be like upgrading your habits. If the replacement habit is healthy or productive, it can help break the cycle of gambling addiction harmful, if not, it is just trading one issue for another. I hope those who go through this choose well.
Hearing about cross addiction for the first time and what came to my mind is "Cross addiction can be a healing process ". To quit an addiction, first the addict has to realize he is actually addicted to a particular habit and realise too the possible consequences of such a habit.
Now, for an addict to realise a particular habit is no longer worth it and is willing to QUIT but adopt a new habit, it shows that it is actually possible for that particular addict to quit his addictions completely.
It will even make a whole lot of sense if his new addiction is a good one or one with lesser consequences just as in the case of the 'friend ' OP stated. All he will be needing at that point is professional help.
We will only condemn cross addiction if the addict is addicted to two or more habits at a time. Or he upgrades from a fair habit to another worst than the former. If this is the case, then it is worst than addiction itself.