In short: Choose alignment behavior that matches the workbook change you are reviewing.
Smart
Smart Alignment fingerprints sheets, rows, and columns, anchors unique content, and realigns insertions or deletions. Both original addresses remain attached to every difference.
Basic
Basic compares A1 to A1 and every other identical address. Use it when address movement itself is the change you need to audit.
Table
Table mode matches records by business keys such as SKU, customer ID, or email. It is designed for reordered datasets rather than formatted workbook models.