An example illustrates why this could be powerful: If an Aetna customer has diabetes, it can be extremely costly (for both Aetna and the customer) for them to frequently see doctors for help managing their condition. Instead, a merged CVS-Aetna could encourage this customer to go to its walk-in clinics regularly for check-ins, potentially limiting those higher-cost doctor visits. A similarly salutary outcome could arise from having patients with other chronic conditions visit these clinics, perhaps to make sure they’re taking their medication—because when they aren’t, their conditions could worsen and they are likelier to need to see a doctor. In this way, CVS-Aetna could reduce the cost of the care it provides, perhaps prompting competitors to lower their prices in response.

The second reason CVS might see an advantage in buying Aetna is a single word that has appeared in a striking number of stories this year about any retailer that wants to keep making money: Amazon. Amazon is thought to be plotting a foray into pharmaceuticals—it reportedly has secured licenses that would allow it to sell, in 12 states, drugs, among other things. It could be the case that the company secured these licenses only to be able to sell medical devices, but analysts expect it has bigger ambitions—perhaps it will start up an online pharmacy that could ship medications. These reports have health-care companies like CVS bracing for the presence of a new, ruthless competitor that has record of completely changing entire industries. The proposed CVS-Aetna merger was not exactly unexpected—the two companies, after first partnering seven years ago, have been growing ever closer—but anticipation of Amazon’s next moves could have hastened things.

From this vantage, CVS’s pursuit of a deal is of a piece with all the other unusual things stores are doing to defend themselves from online shopping, such as installing juice bars and spas. “They’re trying to figure out how to utilize their footprint better, and by merging with an insurer, their hope clearly must be to be driving more foot traffic into their facilities and figure out a way how to be more on the front line of health-care delivery,” says Leemore Dafny, a professor of business administration at Harvard Business School.

Of course, there might be still another reason for the deal, Dafny noted. “There’s a question as to whether these two companies couldn’t figure out ways to get [the same] benefits without merging,” she told me. “Obviously, Wall Street loves mergers.” Indeed, the financial firms arranging the deal stand to earn in the neighborhood of $130 million if it goes through.

And if it does, will it save consumers money or give them better care? Because the proposed merger is between such large companies, that’s a little hard to predict. In general, consolidation in the health-care industry has primarily benefited the companies making the deals. That said, two experts I talked to said that this one could be different. Dafny said she sees more risk for CVS’s shareholders—the company could turn out to overpay for the acquisition—than for consumers. Atul Gupta, a professor at Wharton, agreed: “In the short term it will probably benefit existing CVS/Aetna customers if they start providing some innovative new services or pass through cost benefits to them,” he wrote to me in an email.