I was just reviewing a brief tutorial on W3Schools and after reviewing <span> tags, I have a question. What are they for?

Here's some HTML with <span> tags...

Code:
<!DOCTYPE html>
<html>
<body>

<p>My mother has <span style="color:blue;font-weight:bold">blue</span> eyes and my father has <span style="color:darkolivegreen;font-weight:bold">dark green</span> eyes.</p>

</body>
</html>

And here's some HTML without <span> tags, utilizing other tags...

Code:
<!DOCTYPE html>
<html>
<body>

<p>My mother has <font color="blue"><strong>blue</strong></font> eyes and my father has <font color="yellow"><strong>dark green</strong></font> eyes.</p>

</body>
</html>
So, if I can accomplish the same goal with both, is there a more significant use for <span> tags?


-Jared