doc,stream: clarify 'data', pipe() and 'readable'

We stated that 'data' and pipe() are preferred over 'readable'.
This commit clarifies that 'data' and pipe() are easier to understand,
but 'readable' might result in increased throughput.

Fixes: nodejs#11587

doc/api/stream.md

@@ -754,7 +754,8 @@ end
 ```
 
 *Note*: In general, the `readable.pipe()` and `'data'` event mechanisms are
-preferred over the use of the `'readable'` event.
+easier to understand compared to the `'readable'` event.
+However, handling `'readable'` might result in increased throughput.
 
 ##### readable.isPaused()
 <!-- YAML