Standalone updates can be useful if you want to install the same update again or on another computer. Use the DMG for Flash drive installation and use ISO for DVD Installation or Installing on a Virtual Machines.
Hackintosh Yosemite Installer can be used to install OS X Yosemite On PC without the need of a Mac. Some updates become available only after installing another update. You can back up with Time Machine, for example.
The OS X Yosemite 10.10.5 update improves the stability, compatibility, and security of your Mac, and is recommended for all users. The OS X Yosemite v10.10.5 Update is recommended for all OS X Yosemite users.
