The element is for data that one might find in a spreadsheet, consisting of rows and columns of cells. It's important to ensure that the editing process allows identifying row and column headers.
When you include a list in your page content, this relationship needs to be conveyed visually, and it also needs to be conveyed to people using screen readers.
Headings are important orientation aids, and they help people quickly identify the content on your page. When headings are correctly identified, they also allow screen reader users to quickly navigate from heading to heading.
The heading levels (1-6) are often considered a way of describing and determining the “importance” of a heading, with h1 being the most important.