Cisco Prime is used to monitor and manage network devices like switches, WLPs, and wireless access points. For example, if I have a building with four floors, I can all the access points and sitemap to Cisco Prime, so the next engineer who is working when I'm not available has a clear picture of how the site is configured. There's no need to physically go to the site. He can test everything remotely.
I work for a telecom company on the network service delivery team, and 1,000 engineers on my team use Cisco Prime. There are different teams like monitoring, LAN, wireless, etc. About 10 percent of engineers in my organization use Cisco Prime.