[Koha] SIPServer abaility

Hello, I read a recent message talking about the ability of Koha being able to use a SIPServer. I tried looking in the wiki for more information, but while it seems to explain how to set it up, I can not find a uapication for it? I use SIP server sfor VOIP telephony purposes. But, what is the use here in Koha? Thanks Joeph