Assuming a merchant accept Bitcoin,
You as a shopper, place an order, and that merchant did not deliver, or sent to the wrong address, or sent a fake product.
You can not reverse the payment, you can get your bitcoins back, and the only thing you can do it leave a negative feedback.
Of course, there are many other scenarios, like phishing websites, fake websites, selective scams, and so on
What are your thoughts and ideas to prevent these scams.
there is a big difference here!
when the payment system has charge back it means any random person on the internet with complete anonymity can use any payment method and charge it back.
when it doesn't have it (like using bitcoin) if the merchant pulls a scam you can find him because it is one person not just a random anonymous person on the internet. they can be registered, give their information have a real physical shop,.... and lots of other things to make the trust and people easily use them.