The latest personal finance survey, run on behalf of the banking practice at global consultancy firm McKinsey and Co, has taken a closer look at the rapid growth in digital banking across both "emerging" and "developed" Asia.These trends are being echoed among Australia's retail bank customers.Digital banking penetration in Australia is now at 97 per cent, on McKinsey's numbers, with the number of active digital banking customers "surging dramatically" over the past three years, when the previous survey was run.Smartphone banking is outpacing all other types of digital growth, highlighting the challenges for traditional banks in the region and the opportunities for their online-only counterparts."In a banking landscape with numerous options, incumbent banks must find ways to remain relevant or risk losing customers," the McKinsey report's authors said.The report finds:•    approximately 55 to 80 per cent of customers in Asia would consider opening an account with a branchless, digital-only bank ; and•    35 per cent to 50 per cent of consumers change their buying decision based on evaluation done on digital channels.Some of the main findings for Australia include:•    the percentage of digitally active customers (those who use digital banking on a fortnightly basis and have made e-commerce purchases in the last six months) has grown significantly since 2014 to around 90 per cent in 2017, showing the increased relevance of digital channels for day-to-day customer operations;•    further, digitally active consumers bought approximately 1.6 times more products compared to non-digital consumers in the past 12 months and own around 1.1 times products indicating a strong correlation between digital engagement and value generation; and•    the survey results highlight a significant opportunity for digital banks in Australia, based on the 75 per cent of Australian bank customers in the survey who said they would consider opening an account with a branchless digital-only bank; and those willing to bank digitally would be willing to shift an average 45 per cent of their total wallets to the digital account.The survey covered around 17,000 respondents from 15 Asian markets: Australia, China, Hong Kong, India, Indonesia, Japan, Malaysia, Myanmar, New Zealand, Philippines, Singapore, South Korea, Taiwan, Thailand, and Vietnam.