Another reason to keep the Platinum is I plan to "give" my family members these perks as AU on the Platinum card.
Priority Pass/Delta/Centurion Access. Hilton/Marriott Gold. Global Entre/TSA pre-check.
I would say $175 for up to 3 AU to receive those perks seems pretty fair. I know the 3 family members travel quite a bit so at least they will appreciate it.
Good luck with what ever way you go
With the 100,000 point SUB. Should I apply to what is heraled as the worlds greatest travel card?
$550 AF is a lot for a x5 travel and hotel card with Centurion Lounge that I may use once a year at most.
I agree that you just answered your own question.
It sounds like you're having trouble justifying the AF.
Let's be clear here.
The Platinum is not the world's greatest travel card ... for everybody.
It works well for people who buy a LOT of airfare and want to redeem points at maximum value - which usually requires transfer to airline partners for premium class international travel. And many of them probably put a high value on the best network of airport lounges. So the Platinum is all about airline travel and airports. Anyone who puts only modest to no spend on airfare probably would do much better with other card options. And there are other ways to get the equivalent of that 5x points on hotels with Platinum on other cards at the same or often much less AF.
I travel but not so much airfare. I spend as much or more on hotels, rental cars, cruises, tolls, parking, trains, busses, taxis/limos, etc, so I chose the Chase Sapphire Reserve since it better covers all those other types of travel too. It also has better travel protections than AMEX Platinum. Transfer to airline parters is not important to me. And I dine out a lot, so I can redeem all my travel and dining for effectively 4.5% directly through the UR website without having to try to squeeze that extra 0.5 cents per point by transfer outside Chase. But that option is available if I want to use it.
CITI Prestige and USB Altitude Reserve are also good travel cards in the super-premium category. All credits against AFs don't work well for all people. And there are great lower-cost cards that work better for some people including Wells Fargo Propel, Chase Sapphire Preferred, AMEX Green (for less frequent fliers) and even Navy FCU Flagship.
The world's greatest travel card is the one that works well for your spending and lifestyle.
That said, if you want the SUB you can always accept the pre-qual and cancel the card later. But focusing on a card that works for you over the long-term might be a better option.