Agree with Zitsky...convenience.
And agree with others....the math such that I can follow it, worked for us!
The Silho cruise we booked is an extra pre holiday short cruise. It has LCG (with the Cookie!) , Porch..Seafood Tower, Murano( a bit too long a meal) Tuscan, etc..More than we will need..
nice bars and lounges
two ports KW (great wifi) and Nassau ( Atlantis) , one sea day..for the Spa.. so perfect!
Next we will look for Bermuda on Eclipse..keeping life simple!