buggy apps does not mean our money is "buggy".
the money is still there, just how to access it realiably by the app is the issue.
all bigpay's wallet fund doesnt sit in *someone*'s personal bank account. there is a separate operating account to hold all the funds, all the wallet activities goes thru this account and wallet provider HAS to report to BNM on the account status.
separately, there is an escrow account, committed by the provider, in this case, bigpay. this escrow account is somewhere like 1:1 ratio against the balance in operating account.
e.g. if all the bigpay wallet balances = RM10mil (sits inside operating account), there is a similar equivalent 1:1 fund size in a separate escrow account. think of this is a "guarantor account".
these operating/escrow accounts are governed by the respective (actual) banks where bigpay/provider made agreement with. dont know what are the jargons here, something like both parties are mutually responsible and both accounts are auditable.
imagine the commitment set by AA/bigpay. 1 user = max RM10k wallet size, the amount of total fund size to commit is huge.
there are also reasons why wallet providers are set a certain limit of RM200 (small purse) and RM1500 (large purse) wallet size. only bigpay has a wallet size of RM10k. BNM didnt approve bigpay's this wallet size for no reasons or justifications and commitment by bigpay itself.
not everyone accepts ewallet, let alone see their money on the phone. some would just rather see/touch physical $$ notes or bank booklets as assurance

Why 10k limit? Sometimes buy 4-5 AA tickets needs to swipe 10k.