Added a sentence to draw attention to benefits of t-strings

Author: gtm19

public/introduction.html

@@ -182,7 +182,12 @@ <h1 class="font-serif font-bold text-cloudbank text-3xl">
 print(lower_upper(my_template))
 # "hello WORLD!"
 </code></pre>
-        <p>Okay, you probably don't want to do exactly <i>that</i>.</p>
+        <p>
+          Okay, you probably don't want to do exactly <i>that</i>. But this example
+          demonstrates that the <i>power of t-strings comes not from the template
+          itself, but from the code you (or someone else!) writes to process it
+          into a string</i>.
+        </p>
         <p>So why <i>do</i> we want t-strings?</p>
         <p>Let's start with the useful.</p>
         <p>