## 4 Results and Discussion
### Emerging Digital Payment Technologies
#### 4.1.1 Card Payments  
Card payments are one of the digital payment technology services made available by banks and other financial institutions to their customers. It is a more conventional form of payment compared to other categories, such as e-payments, mobile payments and cryptocurrencies. The cardholders have access to their bank accounts through the use of bank cards and make payments online or via POS machines. All card payment technologies are regarded as easy and convenient ways of making payments. However, they operate with some key differences. Debit cards allow the cardholder to pay from a deposit previously made at the bank, whereas credit cards let the cardholder spend money or withdraw cash from the ATM by taking a certain amount of money from the card service provider [84]. On the other hand, prepaid cards are a convenient way to pay for things when not carrying cash. A prepaid card is a card bought with money loaded on it, so that  
Figure 3: Percentage and number of studies conducted in each category of Digital Payment Technologies.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Digital Payment Technologies** & **References** \\ \hline
**Card Payments** & [11; 13; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46] \\ (Credit/Debit card, Prepaid card) & [11; 13; 35; 36; 37; 38; 40; 41; 42; 43; 44; 45; 46] \\ \hline
**E-Payments** & [8; 11; 12; 13; 35; 36; 37; 38; 40; 41; 42; 43; 44; 45; 46] \\ (SADAD, E-Wallets, Electronic fund transfer, e-banking, eCheck, EFTPOS, & \\ PagoPA, IrFM, Belt \& Road silk Currency, Digital cheques, P2P fund & [11; 13; 16; 37; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60] \\ transfer, Russian PayCash, OPERA (Google Wallet, Apple Pay, & \\ Samsung Pay), GoPay \& OVO) & \\ \hline
**Mobile Payments** & [8; 11; 12; 13; 35; 36; 37; 38; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70; 71  
we can use the card to spend up to that amount. Prepaid cards work like debit cards, but the difference is we do not need a bank account to obtain a prepaid card.  
Out of 58 reviewed papers, 14 examined card payments (Table 5 and Figures 2 and 3) in India, Sweden, Denmark, India, Ukraine, Indonesia and Kyrgyz Republic. The majority of the empirical studies examined card payments in the context of India. This is mainly because several studies were conducted during the period of demonetization to empirically examine the adoption of digital payment systems to provide valuable insights to economists, policy makers and payment service providers. Demonetization triggered citizens to adopt digital payment systems [13; 14; 45; 46; 69]. Post demonetization, and particularly during the COVID-19 pandemic, there was a sudden increase in the usage of card payments in India. For instance, vendors and other small businesses, such as cafes, small restaurants and shops, auto-rickshaw drivers, etc., started using card payment technologies. The government further encouraged citizens to adopt digital forms of payments by offering financial incentives [39; 45].  
[PERSON] et al. [37] studied Sweden, a country known for being a role model of a cashless society. In Sweden, it is the norm for people to pay by card and other methods of digital payment services. The use of digital payment technologies, such as card payment transactions, is increasing in everyday payment processes [37]. Similarly, [PERSON] et al. [42] studied new possibilities of combining card payment data as society becomes more digitalized. They studied the neighboring country, Denmark, where most purchases use credit cards. In their study, the card payment data were used to determine consumer expenditure and environmental footprints of consumption patterns [42]. Card payments also significantly impacted the economy [43]. [PERSON] et al. [43] confirmed that USD 983 billion was added to the GDP of 56 countries through card payments from 2008 to 2012, and this increased consumption by an average of 0.7%.