PI Builder should use tables (the kind of table found in the Insert tab on the Ribbon) whenever headers are set up and whenever data is imported from the PI Data Archive or the PI Asset Framework.
Benefits of PI Builder using tables:
Filters are on by default, and they do not use up the 1 filter that is allowed per sheet
Readable formulas that automatically fill the table column
Explicit isolation of PI Builder data from the rest of the sheet
Banded rows are an option