The integrity of the club's jersey should be worth more than any amount of money.
To a degree I agree with you. But in saying that you are a Dragons fan and the design of the jersey has not changed in 60-odd years. If the Dragons did something like this I'm pretty sure their fans would riot because there is a rich history behind it and would not want it compromised. I remember when they cut the goatee off the big red V and a petition went around to bring it back.
But at the same time, Melbourne does not have pokies revenue to give them an income. If they need to go to "non-traditional" revenue streams (and pokies revenue, in rugby league terms, is traditional) then so be it. Sure they have a sponsorship agreement with Crown but just how much that is worth is different compared to what I imagine Sydney clubs would get from pokies revenue.
So I can level with your statement but I will trot out the trite "rugby league is a business" line as well. The new owners of Storm have said they will do more of this as part of their business plan but they already have the relationship with Warner Brothers (Dark Knight Rises jersey last year) and I wouldn't be surprised to see Melbourne have a themed jersey to tie in with the big WB release every year.
At best, clubs like Saints could allow for movie advertising like the Souths Cinderella man one without compromising the traditional design.