Delta cache is an automatic hands-free solution that leverages high read speeds of modern SSDs to transparently create copies of remote files in nodes’ local storage to accelerate data reads . In comparison, you have choose what and when to cache with Spark cache.

Also

•  Delta cache can be read and operated on faster than the data in the Spark cache.
• Eviction happens automatically on file changes

More details could be found at https://docs.databricks.com/delta/optimizations/delta-cache.html