SINGAPORE/HANOI (Reuters) – Bui Mai Phuong is an avid online shopper, ordering anything from clothing to personal-care products from her smartphone. But she prefers to pay with cash.

Signs accepting WeChat Pay and AliPay are displayed at a shop in Singapore May 22, 2018. Picture taken May 22, 2018. REUTERS/Edgar Su

She is among hundreds of millions of people whom firms such as Softbank Group-backed Grab and China’s Tencent want to win over as they try to tap into Southeast Asia’s burgeoning internet sector.

More than 70 percent of the region’s 600 million-plus people do not use banks – higher than the global average of about 30 percent – and e-commerce is projected to hit $88 billion by 2025.

But convincing consumers like Phuong, who lives in Hanoi, could be tricky.

“I have never tried using mobile payments because I don’t know how to use it and it seems a bit complicated to use,” said Phuong, 36, a manager at a construction material supplier in Vietnam.

Mobile payments are ubiquitous in China; a consumer can spend a day without using cash at all in Beijing or Shanghai, and even some beggars accept mobile payments. But cash remains king in Southeast Asia.

Hard currency, paid on delivery, accounted for 44 percent of total e-commerce transactions last year and is likely to remain the most popular payment option for at least the next three years, according to data by research firm IDC.

“The biggest challenge for users and merchants to adopt cashless is the fact that cash remains ubiquitous, easy to use and inexpensive,” said ride-hailing firm Grab, which has ventured into e-wallets.