This was a good promo and if you spent $3335 on the card, then you would get right over 55,000 miles (including 2 Athorized Users), so that was a transfer of 110,000 Hilton points. I would encourage people to get over 55k, as you can only transfer in blocks of 5,000 miles. If you have to spend $2,500, may as well get it up o $3,335, remeber you get 1.5 miles for each $1 spent.
Also, you don't need to spend on your Authorized User cards, these cards are exactly the same #, so their system has no idea which card you use. This is just like Chase system, essentially same card. Personally, I don't even bother with AU cards, I get them, put them in a draw and eventually shred them.
Final note, this card is churnable, so at current promo with $1 spend at 20,000 miles + 5,000 miles for 2 AUs, that is still 25,000 miles = 50,000 Hilton points, for a $90 fee, that is pretty great deal to include in your churn schedule, IMHO. You do this three times, pick up 150,000 Hilton points, you got yourself 4 nights at Category 7 hotel for $270 -- not too shabby.
Authorized user cards have the exact same card number as the primary, so I am not sure how BofA are even able to differentiate which card is used
Actually they do.
While this is not specific to this card, but as a general matter, the banks know which card is used. You are unable to view it on your statement, (not always but in most cases) but the internal records know which card is used.
The mag tape stores the AU's name and other identifier. I found this out when AU card was compromised and the bank called. They specifically asked if the AU was traveling (the charges were made in Mexico). They knew it was the AU card being used (a cloned one from info stolen, probably at the doctor's office as that was the only place, only time the AU card was used in 3 months' period.), and all transactions were POS transactions. So right out of bat they knew it was a cloned card once they verified the AU did not leave home and the card was in our possession.