The purpose here is to use classes to apply css styles. Inline styling is inefficient and not reusable. If you had a website with 400 span tags you would have to edit each one if you wanted to change the color for example. With a class you would only change the color once.
<span style="font-family: Helvetica; font-weight: bold; color: blue">Starting at $2.00 / frame.</span></p>
The purpose here is to use classes to apply css styles. Inline styling is inefficient and not reusable. If you had a website with 400 span tags you would have to edit each one if you wanted to change the color for example. With a class you would only change the color once.