I guess it’s more useful as a store of wealth than a currency. Like gold it can be transferred irreversibly between owners, except now the transfer and storage costs are significantly reduced and it’s available to the general public as an option. The key benefit is the use of the internet as a transfer medium, you no longer have to rely on a third party to facilitate the exchange, which for most large transactions means paying someone to transport it and store it (lawyers, guards, banks).

It does allow for easy exchange for all users, including criminals, but generally using it for crime is a terrible idea, as every member of the network can see all transactions. Bitcoin is more of a notice board about what addresses have what amounts, and if you can prove to the people that post on the notice board that you control an address, you’re allowed to spend the contents and update everyone of where you sent it.

People came up with an idea for how to do chargebacks, it’s called an escrow service, a third party that holds the money until all parties have had a chance to raise a dispute and confirm they are happy. This is the same as how PayPal works, trust based on reputation of the escrow provider, and the escrow provider is payed a fee. It’s just that now with bitcoin, you also have the option to complete the transaction online without an escrow provider, the same as you would in person with cash.