Grabpay/Ali pay is potentially best acceptable outside of Singapore, but not guaranteed. I mean you can avoid cash if you avoid hawker centers and probably food courts... Everything else (grab/MRT, fancier restaurants, fast food) should accept card

(Aka get cash if you really want to roam around and eat at hawker centers, or local bakeries/restaurants that take only cash)

Paylah/paynow - believe Singapore only, and you need a singpass(local ID)/local bank account for these? Maybe paynow allows foreign traveler with HSBC acct

https://www.hsbc.com.sg/ways-to-bank...ings%20account.