Yes, go ahead and waste money on non swing states.
If she has a huge cash/staff advantage over Trump, then the swing states will hit diminishing returns hard. At that point the marginal value of each dollar spent elsewhere becomes higher.
Also, if Trump is spending $0 in swing states, both on ads and staff, why would you dump all your dollars into 5 or 6 states when you can force Trump to play defense literally everywhere. The idiot is campaigning in Texas and Georgia and talking about winning Connecticut and New Jersey. She puts what, 1 staffer and 10k in ads in Georgia... he'll bite and go back their to campaign, wasting his time and money. This is a tactical decision to goad Trump by reassuring him his bullsh**t strategy is correct.