The development of credit cards reflects the diminishing materiality of money.

Evidence

Money is now more likely to be numbers and digits on statements and invoices than physical coins and notes. — Neil MacGregor, A History of the World in 100 Objects, 1497

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 1497
• XREF: connects to: Money economy reduces persons to quantitative exchange value — Georg Simmel, on individuality and social forms_…, 750; Negative real interest rates drove capital into collectibles and artworks — David Harvey, The Condition of Postmodernity: An…, 1879