It avoids installation failures caused by fluctuating internet connections during the setup process.
This is a highly compatible "in-place" update for 4.5 and 4.5.1 and is available at the Microsoft 4.5.2 Offline Installer page Why Use the Offline Installer?
: The standalone package (approximately 66.8 MB to 982 KB depending on the specific patch version) is ideal for environments with limited connectivity or for redistribution within other software installers. Pros & Cons