You are correct that there is a public ledger. However, your wallet address doesn't require or display your name, email, phone number, etc.

For example, if I purchase something at Target and use my debit card, my bank knows what I spent, when I spent it, where I spent it, and earns a fee for the service. If I use my Target red circle information, Target has even more informaiton (exactly what I purchased).

With crypto and decentralized wallets, a direct purchase can be anonymous (only my wallet address is known/used) and the vendor doesn't have to pay 1-2.5% transaction fee.

Thank you for reading and commenting!