Well welcome to the Platinum club CruiseDad. While yes, you would have gotten VIP boarding with the suite anyway, that is ALL you would have received.
With Platinum status you also get other goodies- Free laundry service. (not dry-cleaning just wash and dry) which is a great thing if you want to be able to travel light. You get a free entry (for each Platinum guest) to either the Blackjack tournament or the slot tournament (even if you are not a gambler, its worth a shot at one of those for the $500 prize)
You get canopies delivered to your stateroom, a platinum gift (which I think is a small cooler at the moment, they change it every so often)
You get to use the VIP line at the guest services desk, just flash your platinum S&S card. This can be great when there is a long line. You get priority tendering.. even better.. if you want off the ship first thing you do not have to wait for the ship tours to leave, you can simply go down to the tender gangway and show them your card and they will get you on the next tender. There is supposed to be the same returning to the ship but the enforcement is not the best since Carnival does not always have control over the tendering on the return. Priority disembarkation too. Oh and priority spa reservations.
I'm sure I left a couple of things out... but these are the most commonly used perks by us.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013