Clarify possible uses of uint

Improving-performance-with-Viper-code.md

@@ -264,7 +264,12 @@ int() casting is very fast in viper code.
 
 ## The viper uint data type
 
-This data type is in most aspects similar to viper `int` but the range is 0 to 2\*\*32-1, i.e. it's a unsigned 32 bit integer.
+This data type is in most aspects similar to viper `int` but the range is 0 to 2\*\*32-1, i.e. it's an unsigned 32 bit integer. Typical uses could be:
+
+* As return type hint when return values could fall between the maximum `int` value and 2\*\*32-1
+* For unsigned int arithmetic, in the range 0 to 2\*\*32-1
+* For pointer arithmetic, see `ptr` data types below
+
 
 The uint() cast function will return the last 4 bytes of `builtins.int` as a unsigned 32 bit int.