Despite improvements in technology, most consumers remain skeptical of mobile wallets, often testing them once or twice before abandoning the idea and returning to traditional payment methods.

So what feature will finally make a “killer” mobile wallet app?

It won’t be rewards. Rewards cards are frequently used as the payment vehicle for mobile wallets; however, rewards are expensive for credit card companies and generally subsidized with interchange. The difficulty of using an app instead of a plastic card is that issuers are not able to offer better rewards than those already available. Also, if interchange rates in the U.S. follow those in Europe, even current rewards programs may not be sustainable.

Payment account optimization is the way to go. Although not as alluring as rewards, transaction optimization might be the best opportunity for banks to provide a “killer” mobile wallet. Using transaction patterns, balances and payment schedules, a future mobile wallet might be able to make an educated recommendation for which account to use for a particular transaction, as in the examples below.

Grocery store visit. Trips to buy food for the family tend to follow a fairly regimented schedule. A “killer” mobile wallet will recognize this trend and suggests which account to use based on grocery-related rewards.

Gas station purchase. Mobile wallets in the future will remember that one of your credit cards provides a rebate on each gas purchase. The mobile wallet will confirm the credit card has sufficient funds for a typical gas purchase and suggest the appropriate card to receive the optimal reward for the transaction.

Electronic upgrade. When making a large electronics purchase, the mobile wallet app will recognize the total cost is higher than a typical transaction. Based on available funds and account patterns, the mobile wallet will realize the purchase will likely be paid over several months, so it suggests a credit card with a lower APR to take advantage of the lower interest to account for the lack of rewards.

Home improvement. When purchasing kitchen appliances and cabinets for a home renovation, the “killer” mobile wallet will check your home equity line of credit and suggest that account for the household upgrades.

In each of these cases the user will have the option to override the suggestions based on individual circumstances. However, this level of transaction optimization might by the feature that increases adoption and continued daily use of mobile wallets.

Large banks have already announced proprietary mobile wallets will allow customers to view account balances before a purchase, so transaction optimization might be in the not-so-distant future.