Splitting partitions is an alternative to deleting the partitions and creating new ones using software such as fdisk, the advantage of which is that the data is not lost. The most common use is installing multiple operating systems on a single computer.
FIPS only works on primary partitions that are formatted using the File Allocation Table (FAT) filesystem. Most new machines with Windows pre-installed use NTFS, leaving FIPS obsolete for its intended purpose of resizing existing Windows installations to install Linux. In addition, FIPS cannot grow partitions due to technical limitations with the design, and partitions shrunk with it have some wasted space since it does not shrink the File Allocation Table. The filesystem to be shrunk must also be defragmented before FIPS is run - since FIPS does not move data, any data near the end of the partition prevents it from being resized.