Add "Why Tini?" section in the README

Adds a summary of #8 and a link to that discussion.

README.md

@@ -20,6 +20,24 @@ and wait for it to exit all the while reaping zombies and performing
 signal forwarding.
 
 
+Why Tini?
+---------
+
+Using Tini has several benefits:
+
+- It protects you from software that accidentally creates zombie processes,
+  which can (over time!) starve your entire system for PIDs (and make it
+  unusable).
+- It ensures that the *default signal handlers* work for the software you run
+  in your Docker image. For example, with Tini, `SIGTERM` properly terminates
+  your process even if you didn't explicitly install a signal handler for it.
+- It does so completely transparently! Docker images that work without Tini
+  will work with Tini without any changes.
+
+If you'd like more detail on why this is useful, review this issue discussion:
+[What is advantage of Tini?][0].
+
+
 Using Tini
 ----------
 
@@ -225,6 +243,7 @@ Special thanks to:
   + [Asko Soukka][41] for packaging Tini for Nix
 
 
+  [0]: https://github.com/krallin/tini/issues/8
   [10]: https://github.com/krallin/tini-images
   [20]: https://github.com/krallin/
   [30]: https://github.com/tianon

tpl/README.md.in

@@ -20,6 +20,24 @@ and wait for it to exit all the while reaping zombies and performing
 signal forwarding.
 
 
+Why Tini?
+---------
+
+Using Tini has several benefits:
+
+- It protects you from software that accidentally creates zombie processes,
+  which can (over time!) starve your entire system for PIDs (and make it
+  unusable).
+- It ensures that the *default signal handlers* work for the software you run
+  in your Docker image. For example, with Tini, `SIGTERM` properly terminates
+  your process even if you didn't explicitly install a signal handler for it.
+- It does so completely transparently! Docker images that work without Tini
+  will work with Tini without any changes.
+
+If you'd like more detail on why this is useful, review this issue discussion:
+[What is advantage of Tini?][0].
+
+
 Using Tini
 ----------
 
@@ -225,6 +243,7 @@ Special thanks to:
   + [Asko Soukka][41] for packaging Tini for Nix
 
 
+  [0]: https://github.com/krallin/tini/issues/8
   [10]: https://github.com/krallin/tini-images
   [20]: https://github.com/krallin/
   [30]: https://github.com/tianon