Amazon Aurora is a managed database service known for its ability to automatically scale in response to an application's workload demands, both in terms of compute and storage. This makes it an ideal choice for web applications with unpredictable traffic patterns as it can handle spikes in workload without manual intervention. Other databases such as a self-managed database on an EC2 instance would not provide the same level of automated scaling and would require manual scaling activities, which is less suitable for unpredictable traffic. Amazon Redshift is more focused on data warehousing solutions and does not offer the same elastic scaling capabilities for OLTP workloads. Amazon DynamoDB is a NoSQL service, which would not support relational database requirements.