The bottom line: In many ways, the money primary is not important because money is important, but rather because it helps determine which candidates are taken seriously by the media.
A bare minimum of money is necessary to staff a campaign, keep it on the road, and keep its vital functions on track — although Trump might have effectively disproved even that. Beyond that bare minimum, money tends to go in two directions: consultants and TV ads.
Candidates still spend the lion’s share of their funds on TV ads, because that’s where the boomers are, and boomers are very likely to vote. But TV ads are hard to target effectively, and they always come at a premium: Many swing-state local TV stations are happy to lose money three years in a row, just because they know that presidential election campaigns will be like money from helicopters.