We bought 8 of them on our Hawaii cruise in Aug 2017. We are a family of 7 so we normally have to book 2 rooms each cruise.
Our onboard account was charged $2000 and OBC of $1000 was also applied. The net charge to our credit card was $1000 + what we had spent on that cruise. We did not change our normal spending habits because of the OBC. Just did our vacation. Not matter how you do the math we are getting a $1000 of "VALUE" at no cost as long as they are all used within the 4 years.
We just used 1 for an Alaska cruise in September and have 7 left. But are currently looking at 2 balconies on a cruise next March where we will be able to use 4. Which will leave us with 3 left, which I don't think we'll have a problem using.
In our case because we are Canadian the "Deposit" was converted to CAD. So our cruise cost $2100.08 CAD and our $250 USD deposit was applied as $324.00 CAD. Which means we owe $1776.08 CAD on final payment.
According to xe.com 250 USD is currently worth $334.10 CAD so they are taking some off the top. However at the time of purchase the exchange rate was $1.23 so we paid $1230 CAD for $2000 USD of credits which if all spent today would be worth $2592 CAD so my net "VALUE" is $1362 CAD.
The good thing is had the exchange rate gone the other way we have the option of paying in USD and using them as is.
But now I'm really making it more complicated for those who say it's too complex... LOL.