Assuming you mean a filter that uses the LOOKUP() function, that's a table calc, and it lets you filter what's on your sheet without deleting actual rows from the underlying table.
A basic quick filter (usually hooked to a dimension field, and where you select dimension values from a list) will eliminate from the underlying table the rows with the values you de-select from the list, and add those rows back in when you select them on the list. But if you have removed rows, then operations like summing up the total sales for a country will be incorrect if half the states have been removed from the table.
A table calc filter (such as LOOKUP) keeps the table intact, and just controls what part of the table is displayed on the sheet. If the whole table is still there, then a sum of sales for the entire country will be performed correctly, for example.