I started implementing hasEnrolledInstrument in Chrome according to the WG agreement [1]. It will be great if this API and the change to canMakePayment can be added to the spec language. I'd like to kick off an Intent to Ship thread in blink-dev@ soon as an official announcement of the canMakePayment behavior change to web developers.

[1] https://lists.w3.org/Archives/Public/public-payments-wg/2018Nov/0018.html