Use Topics Covered on a speaker when you want that speaker to appear under one or more event categories before their talks are confirmed, or when the category should be attached directly to the speaker rather than only inherited from their talks.
First, make sure categories are enabled for the event. Then go to Content > Speakers, add or edit the speaker, and use the Topics Covered field in the speaker details step to select the relevant categories.
Those topics can help attendees find the speaker on public event pages, including category and speaker views. If the speaker is already linked to talks that have the right categories, you usually do not need to add the same categories again on the speaker record.
