Many banks have put mobile devices front and center in their marketing and product strategies. But a new study by Millward Brown Digital shows that people vary their technological devices for financial services according to their generation and the specific task involved.

The study of 1,018 adults who own or have access to smartphones or tablets, conducted in October 2014 has big implications for banks. It suggests that banks may be at risk of ignoring the primary device that all generations use for financial tasks: laptops and personal computers.

Millennials are certainly a mobile-centric generation. But as both the length of the task and its importance increase, all generations — even millennials — are more likely to use a laptop than a smartphone.

When it comes to financial services, only 8% of millennials prefer to use a smartphone to submit a checking or savings account application, versus 46% who prefer to use a laptop. Similarly, 17% of millennials prefer to use a smartphone to submit a credit card application, versus 57% who opt for a laptop. Clearly, shopping for a checking account is not the same thing as shopping for a pair of shoes.

In fact, across all generations, people's preference for using smartphones declines sharply as length of time for an activity or transaction increases. Eighty-one percent of consumers prefer a smartphone for tasks under five minutes. Only 43% prefer a smartphone for activities lasting 10-20 minutes. The opposite pattern is true with laptops, with preference for the tool increasing sharply after the 10-minute mark and surpassing smartphones at about 20 minutes.

Researching financial products, obtaining an insurance quote, and opening new checking or credit card accounts all take longer than five minutes. At that point, device preference for smartphones declines dramatically.

This has big implications for the usefulness of tools offered by companies like BankMobile, which offer mobile application options that use a photo of a driver's license to prefill application forms. Most shoppers across generations will think that application times are too long for a mobile device.

But while consumers across generations seem reluctant to engage in acquisition activities on mobile devices, they appear open to servicing and managing their accounts on smartphones and tablets.

For activities like checking the balance of a checking account, millennials skew slightly towards smartphones, while Gen Xers and baby boomers still prefer laptops. Thirty-seven percent of millennials have a credit card app downloaded on their phone. This is a far higher proportion than Gen X (26%) and baby boomers (13%).

Keep in mind that many of the brief servicing interactions that do occur on mobile devices are through the mobile browser site as well as in-app. Concerns with security and privacy and the size of the keyboard continue to be barriers preventing consumers from expanding mobile engagement in the near-term.

Tablet usage is highest among Gen Xers, with 34% using them regularly. But even among this group, almost all prefer either a smartphone or a laptop for financial tasks.

Tablets are used as a "lean back" device for entertainment, not a "lean forward" device like a laptop where consumers take care of important tasks. At first glance, the tablet would seem to overcome smartphone barrier of using a small screen to enter detailed information. But research shows that consumers continue to reach for their laptop for productivity-driven financial tasks over tablets.

Given consumers' rapidly changing behavior across screens, banks need to dig into how people use each device for specific financial activities in order to engage with consumers successfully.

Many consumers use smartphones or tablets, but they are not necessarily using them for financial services activities. Therefore, if a direct response ad or offer reaches a prospective customer on a mobile device, they are currently unlikely to complete an application from that device. On the other hand, short mobile ads to build brand awareness or remind current customers of mobile services may be very effective at increasing engagement with those services and diverting customer service tasks from branches or call centers.

Mobile may be the future of banking. But laptops are still the now.

Ananda Jaakson is financial service sector lead and Jennifer Canfield is vice president of client and market development at Millward Brown Digital.