No chargebacks is not a problem for Bitcoin customers
Some people may think that while Bitcoin removes risks of fraudulent chargebacks for merchants, it also reduces security of the customers. This is not entirely true. In many ways, security is improved for the customers as well.
Historically, credit cards worked this way: you give the merchant your personal card number and they ask your bank for some amount. They can easily charge any amount they want, or (what is more typical scenario) your card number can be stolen and used somewhere without your consent (the problem is called “identity theft”).
Since it is so easy to charge you any amount of money and you tell your credit card number to thousands of merchants, it is very easy to get in trouble quickly. Credit card processors recognised that quickly and provided a “solution”: you can dispute any charge within several days (or months). To drive adoption of credit cards, disputes were promised to give you money back instantly without much questions, so it would be a job of a merchant to prove if you really have paid for an item. Since there were no real secure solution, risk of fraud was not reduced, but merely shifted on merchants who priced it in. This made credit card payments quite expensive (try buying something worth $1 using CC from a small or medium-sized merchant) and the worries of the customers were not fully addressed. You still have to check your bank balance from time to time to make sure nothing bad happened.
When PayPal and others started making payments on the internet easier, they had an opportunity to improve security greatly. With PayPal you don’t give your identity to every shop, so the risk of fraud is greatly reduced. However, since PayPal itself was using credit cards, it was itself a subject of chargebacks. Also, the security on the web was far from perfect. People used weak passwords, had trojans and keyloggers on their computers or simply sent their passwords in response to fraudulent emails. Two-factor authentication with mobile phones was not yet possible, so PayPal and other payment processors had to allow chargebacks as well.
Bitcoin approaches the problem from an entirely new angle. You physically own all your money, not your payment provider. In addition, you never give anyone access to all your money. Instead, your trusted device signs a specific transaction with a fixed amount and fixed destination address. No one can redirect payment or charge you more. Also, it is very cheap to move money between different wallets, so you can keep your money securely in different locations. Even if keeping money with a 3rd party is convenient, it is an option, not a requirement. And with modern smartphones it is easy to have two-factor authentication to avoid using passwords at all.
This means, that when you pay with Bitcoin, only that much is leaving your wallet. There is no information that merchant could possibly leak to allow someone to spend your money. The only risk is a fraud on part of the merchant (e.g. not shipping the product). As experience shows us, it is not a major problem. Comparing to anonymous customers, merchants are often invested in their reputation and have no interest in making people unhappy. And the more customer wants to pay, the better reputation will be required from the merchant. And if you have a problem with a $3 purchase, it’s usually not a big deal. In the end, customers pay less because merchants have lower risks, can pay small amounts that are not possible with credit cards and don’t have to worry about one of thousands of merchants stealing or leaking their credentials.
For complex risky cases one can always resort to a trusted 3rd party (escrow) that provides dispute resolution and chargebacks. But it is not needed for everyday purchases from well-known merchants.