Hey @Phani1 !
I have had a few cases where we have seen huge improvement when moving to SQL Serverless. Processes that used to take hours in Synapse went to minutes with Serverless. Unfortunately i don't have cost benchmarks.
About use cases, Databricks can be used for streaming, while Synapse has no support for Spark Structured Streaming. Also, Synapse's dedicated pool is very different from Databricks Serverless SQL, as DP involves proprietary storage and has no separation of compute and storage.
What worries me the most about Synapse today is that although it is a great no-code tool, it no longer receives new features, so it is expected to become outdated soon. For example, Synapse does not offer row level security or column masking, nor structured streaming (as mentioned before) and will not get these features as it is in end-of-life.