On our Royal Caribbean cruise the drinks package was very expensive and both adults needed purchase. It would appear you would need to drink an awful amount of booze to make it pay, something my wife and I would not do. On the other hand, paying at the bars will cost as well. You are not allowed to bring your own alcohol on board, nor bring alcohol back from day stopovers. They look for alcohol during their 'security' checks when coming back on board. All very tricky.
Smuggling booze on board is very big. Do some research online or you tube. You can purchase containers that look like shampoo and conditioner bottles for smuggling, there are special moulded soft containers to wear under your clothes, and lots more inexpensive ideas to get you favourite drinks on board.
Like most thinks, when big brother says you are not allowed to do something, people will work out a way to do it.
Being poor and tight with $$, we decided to drink water in most cases, while sometimes having a softee from our son's soft drink package, which was good value !!
Have a great cruise !!
Paj