USB flash drives embedded into credit card have been in existence for a while now - https://www.amazon.com/s?k=credit+card+flash+drive , integrating hardware token into it and delivering it as standard credit/debit card might address the accessibility issues to some extent as we're used to keeping our credit cards relatively safer than a separate hardware key fob.

I doubt whether these credit card 'shaped' USB flash drives are of same thickness as a normal credit card, if not then reducing the thickness of hardware key fob would drive the costs further up and thereby defeating the purpose entirely.