Spreadsheets contain not only formulas and calculations. Very often it contains "database"-like values. No formulas, no calculations, just set of values with primary key and optional heading, which describes data stored in columns.
This type of data can't be processed with usual comparison algorithms. xlCompare determines if the data has database structure and selects appropriate algorithm for comparison.
In this section you'll find various features specific to the "database" comparison - join 2 lists of data, intersect 2 lists and more ...