$3k in three months
Looks like you were right: She'd have to spend $3k in the first three months to get the 100,000 MR points.
If she were to be a FF like me, and could take advantage of Priority Pass, the $200 airline credit and reimbursement of Global Entry, I would think it'd be a good deal. If not, then perhaps no, if she can't take advantage if the benefits.