I just asked the question in a separate post before seeing yours, but I questioned this as well. Would it have been better to have a separate instance of Dynamo

I just asked the question in a separate post before seeing yours, but I questioned this as well. Would it have been better to have a separate instance of DynamoDB independent from the one customers are writing to? I understand this is added cost/overhead, but it would have resulted in isolating the failure to the customer side only, I'd think.