Updated Cloud Cache Benefits (markdown)

Cloud-Cache-Benefits.md

@@ -49,6 +49,13 @@ However, how to make SeaweedFS work with data already on cloud?
   * Can transparently switch to different cloud storage vendors.
   * Can detach from the cloud storage if decided to move off cloud.
 
+# What SeaweedFS Cloud Cache is not?
+
+* It is not a proxy. Many existing tools, e.g., rclone, can proxy requests to cloud storage. Proxy is not ideal for low-latency read or write operations.
+* Its cache size is not limited. With unlimited size, all file content can be localized. So the read can be fast even on the first attempt, without worrying cached items are evicted due to capacity.
+* Its cache is not write-through. 
+* It does not need to link to the original data source. After caching all the file content, you can choose to detach from the remote storage.
+
 # Why SeaweedFS Cloud Cache?
 
 There are other products also cache S3 data. What makes SeaweedFS Cloud Cache better?