Integrate with Stripe's Issuing platform to track the issuing balance and transactions like is already in place with their credit card processing platform and with many traditional small business credit cards at many banks, that way payments can be easily reconciled and transfers into the balance from a bank more easily tracked.

After that minimal integration is in place addon features that would help:

the ability to tie a card to a vendor in zoho to auto tag transactions on a virtual card to that vendor when vendor specific cards are used to control (and optionally an ability to create vendor or even bill specific cards in zoho)

the ability to link an issues card to an expense user and maybe even manage the issuing of the card directly from zoho

ability to manage spend limits and/or do real time authorization integrated with zoho data, like limits for expense card transactions not yet approved, so when an expense is turned in and approved that amount becomes available on the card again (ex. $500 limit in unapproved expenses), also ability for vendor specific virtual cards to have either limits or real time authorization tie into open bills or purchase orders to limit transactions to the outstanding amount or to only specific amounts of open bills.