I have a new Marriott credit card. (Switched from old chase one for one with better attributes)
My wife had a supplementary card linked to my old card.
I signed up for a new card and cancelled my old one as the ofer is most luctraive
free night yearly
5 points per dollar at Marriot hotels
15 nights towards status per year
1st year no fee
All very good and now wondering if my wife should apply for the card to instead of having a supplementary card of mine
It sounds appealing if she can also get 30,000 point bonus & free night per year. It depends on how many nights per year you stay. As you are platinum level then perhaps you could use her card & rewards number for leisure stays. Then she would move up the elite level which would be beneficial if she stayed at properties without you. Also you would then both have access to any future bonus offers from credit card or Marriott. Having applied for a few cards over last year with bonus offers you do need to make sure that she will get the card. I don't know your circumstanses so please don't take personally. These offers can be very good but if you do not get the card then it affects your credit rating. If this is not an issue for you then seems like a reasonable idea. Ensure to read all terms & conditions to check that she would be entitled to the bonus. All of these cards tend to have different policies. Good luck in deciding.
The downside to booking up leisure trips in your wife's name though would be the lower bonus from platinum 50% to silver 20%. Also not able to access facilities available to platinum members. Therefore the 30,000 points & free night are really the main differences between her having a card or supplementary card holder. Is the annual fee that would be paid worth the free night? Could use for one year without fee then cancel?