That's what obfuscating coins like Monero or ZCash (with private transactions) are for - in theory. In practice no exchange directly offers conversions between

That's what obfuscating coins like Monero or ZCash (with private transactions) are for - in theory. In practice no exchange directly offers conversions between those and "classic" currencies so you have to somewhat awkwardly convert via a more commonly used cryptocurrency. Oh and if anyone ever finds a deadly bug in the protocol transactions might be de-anonymized in the future. On the other hand if you pay digitally with "classic" currencies today, your privacy is severely diminished as well. Fintech companies often rely on third parties for some aspects of their services and financial data has special legal standing making it harder to control like you could do with other personal data (under the GDPR, for example).