Difference between Format and Quick Format

When installing new copy of Windows you must have noticed following options:
•    Format the partition by using the NTFS file system (Quick)
•    Format the partition by using the FAT file system (Quick)
•    Format the partition by using the NTFS file system
•    Format the partition by using the FAT file system
•    Leave the current file system intact (no changes)
Why Microsoft has given two options of regular format and Quick Format when one is sufficient? If you do not know the difference between the two then here are the points.
Quick Format:
Quick format permanently removes the file from the disk but does not scan the partition for bad sectors. This option should be chosen if the drive has been scanned earlier and you are sure that the disk is not damaged.
Regular Format:
This format not only removes the files permanently but also scans the disk for bad sectors hence the time taken for this format is more than the Quick format. Use normal format to avoid future disk errors in the drive.