The biggest banking deal since the financial crisis has more to do with technology than any traditional bank metric, CNBC's Jim Cramer said Friday of BB&T's pivotal $66 billion commitment to buy rival SunTrust Banks.

"To me, this BB&T merger of equals with SunTrust is about keeping up with the Joneses — in this case, keeping up with the Wells Fargos, the J.P. Morgans and especially the Bank of Americas," he told investors. "These financial titans can spend fortunes to build out terrific cloud-based customer relations platforms that have done a phenomenal job of adding new clients. On their own, neither SunTrust nor BB&T can really compete with the big boys when it comes to technology."

But the analysts covering BB&T don't seem to understand that, the "Mad Money" host said after listening to management's conference call about the deal.

On the call, they mostly asked about "the old nuts and bolts of banking" — topics like capital ratios, regulation, loan growth, the two banks' cultural fit — rather than focusing on what's next in banking technology, he said.

"I think technology — specifically, the need for customer relations management software — is a crucial part of what drove this deal," Cramer argued, pointing to what he saw as Bank of America's lead in the digital banking arena.

In its most recent quarter, Bank of America reported 36 million active digital banking users, versus 31 million three years ago. The bank also said that 77 percent of its consumer deposits were digital, up from 67 percent three years ago.

"Right now, Bank of America is the king of mobile. They have an incredible app, and they have Salesforce to help them figure out what their customers want and when they want it, and they integrate it together," Cramer explained. "That's why Bank of America has such strong account openings [and] such big deposit growth, because people want to bank on the app, not [at] the brick-and-mortar branches — these have become expenses, not investments."

And the people opening accounts at Bank of America aren't just tech-savvy millennials, Cramer said; they're people transferring from other banks, which the "Mad Money" host called "the best kind" of customer acquisition.

"I think this SunTrust-BB&T deal may be more about playing digital defense than offense," he said. "It's about giving the combined company the scale to invest more heavily in technology, and less in brick-and-mortar, in order to keep those clients happy in a digital world and get some new clients — keep them from migrating to Bank of America."

The problem? Wall Street is choosing to focus on traditional success metrics and turn a blind eye to the power of companies like Salesforce when it comes to cutting costs by upgrading tech, Cramer said.

"My conclusion? If you want to understand the future of the banking business, you need to understand the technology that's transforming the industry. Otherwise you'll miss what's really going on," he said. "These analysts, they don't get the digital imperative, and that's the force behind, I think, what's happening with this transaction."

BB&T's stock traded lower on Friday, sinking 0.44 percent to $50.24 a share by day's end. SunTrust's stock also shed roughly 0.54 percent, closing at $64.37 a share. Their all-stock deal, which will create the country's sixth-largest bank, is expected to close later this year and will likely undergo a series of regulatory hurdles for federal approval.