What is benefit of using table headers?

Answer 1

Table headers are automatically bolded. They are used as column titles. They also are useful for separating the styles of heads and data

Answer 2

They automatically golden the text! instead of nesting <b> in <td> tags you just use <th>

Answer 3

Beyond carson's answer, table headers are also automatically centered and can be used for row titles. Having titles of the table separated from the other cells makes using getElementsByTagName available to access those cells.