But the deal may actually mean more to Energizer investors. First, the transaction put a decent valuation on Duracell's business. Adjusted for the cash that P&G will put into the company, the deal valued Duracell at about seven times trailing earnings before interest, taxes, depreciation and amortization. That should provide something of a floor for the business despite its recent challenges.
The benefits don't end there. Energizer will probably be happy to see Duracell change hands because Buffett will run the business in a different way when he takes over in the second half of 2015. Under P&G, Duracell has fought aggressively for market share, making the business tougher for rivals like Energizer.
Indeed, Duracell's market share has risen to 35 percent from 27 percent since 2009, according to RBC Capital Markets analyst Nik Modi. He added that Duracell hasn't followed Energizer or Rayovac on price increases during that time.
Read MoreBuffett on stocks: 'Look at them as a business'
Modi points out that Duracell has sacrificed significant profits while under the ownership of P&G: The division has an operating margin of 18 percent—lower than when it became part of P&G in 2004 or even when Gillette bought Duracell in 1996. P&G declined to comment.
Buffett, however, is more likely to focus on cash flow. At least one other Buffett deal shows that he tends to focus on profits over market share: Since Buffett acquired condiment giant Heinz with 3G Capital, the company has reduced promotions, Modi said. Berkshire Hathaway didn't respond to a request for comment from CNBC.
Perhaps even more exciting for Energizer investors is the potential for a strategic buyer to scoop up the company's personal care business. That division, whose biggest brand is Schick razors, will become a separate company through a spinoff planned later in the year ending in September 2015.
Of course, spinoffs don't always work out and can indeed be risky moves. As separate companies, Energizer and the personal care business will arguably be less efficient since they won't be able to share certain overhead expenses.
Read More Berkshire Hathaway to buy Duracell battery business from P&G
But there's good reason to believe Schick will soon wind up in the hands of a strategic buyer. The razor market is dominated by just two brands, with P&G's Gillette controlling 66 percent of the global share in 2013 and Schick at 18 percent, according to data provider Euromonitor.