Hello @AlDunn and welcome to the Community. HSBC has offices in many countries. The Google Wallet Bank List has bank participation by country. Because of banking laws, HSBC in Canada is 'different from' HSBC in the US for this purpose. Individual banks decide whether or not they want to participate in Google Wallet for Fitbit. Where do you live?
Laurie | Maryland
Sense 2, Luxe, Aria 2 | iOS | Mac OS
Take a look at the Fitbit help site for further assistance and information.
@AlDunn Fitbit never supported HSBC UK (neither in Fitbit Pay nor Fitbit's Google Wallet). I have also an HSBC UK account and that card never worked with Fitbit. The mobile version of Google Wallet is a different product supporting a different list of cards.