Saves you time: It is an efficient way of keeping track of your references, and avoids having to type out each reference manually.
Ensures consistent referencing: There is less room for error, compared with referencing manually. Referencingstyles in these software packages can output references consistently and accurately.
Helps you to keep track of what you have read.
Allows you to keep your research organised: You can store your references in one place in a systematic way.
If you are a researcher, some reference managers, e.g. Mendeley, have embedded social media functionality, where you can 'follow' other researchers, join groups of researchers with the same interests, or create your own groups.