Point out why using go-cache might be desirable

README

@@ -1,11 +1,14 @@
 go-cache is an in-memory key:value store/cache similar to memcached that is
-suitable for applications running on a single machine. Any object can be stored,
-for a given duration or forever, and the cache can be safely used by multiple
-goroutines.
+suitable for applications running on a single machine. Its major advantage is
+that, being essentially a thread-safe map[string]interface{} with expiration
+times, it doesn't need to serialize or transmit its contents over the network.
+
+Any object can be stored, for a given duration or forever, and the cache can be
+safely used by multiple goroutines.
 
 Although go-cache isn't meant to be used as a persistent datastore, the entire
-cache may be saved to and loaded from a file (or any io.Reader/Writer) to recover
-from downtime quickly.
+cache may be saved to and loaded from a file (or any io.Reader/Writer) to
+recover from downtime quickly.
 
 == Installation