This kind of story comes up every election cycle.
Candidates spend money in states they know they will lose for a variety of reasons: To reassure state and local candidates, to fulfill commitments made to donors who have an interest in those states, and of course, kickback schemes to share the wealth with media outlets and ad buyers, to mention a few of the reasons.
Yep various reasons and you named a few of them.
Down ticket winners help her if she is elected.