Callum Green notes the trade-offs between using a Header versus a Title in a Power BI slicer visual:
o Header can have an Outline, which includes the ability to underline text.
o Header is constrained to displaying the name of the attribute (“Product Category Name”), whereas a Title can be customised (“Select Category”). You can rename your source data attribute to get around this, however.
o Title enables you align the text, but this is not possible with a Header.
o Header contains the “Clear Selection” option.
It’s not usually great to have both, but there are definitely trade-offs.