It's moot point since it is expired. But I would have to do the math.

She would get United Silver(big benefit in my mind), 50% bonus points on stays, check-in points etc. There are also times where it would have been beneficial for the family to split stays ie summer bonus, megabonus, when we stay at a FS property I only get credit for 1 of the rooms (we always need two when traveling as a family-so now we have to choose between lounge, free breakfast for all etc or the night credit.) For instance we traveled to NYC/Philly this summer and having all of us getting lounge access/free BF saved us $125 plus per night or almost half the room cost. So I booked both rooms under my name-if she was platinum she could have booked one of the two rooms and got credit for one night)
Over time my plan is to transfer all the points she accrues over to me as well so I will get enough points for LT Platinum. (have more than enough stays for gold, moving into 600 plus nights but I am barely over 700K points lifetime)

In the end it doesn't matter since the offer appears expired