Data centers provide separate room for dedicated server because of its size and the conditions it required. The basic need to run a dedicated server for 24/7 is a continuous power source. Data center always have back-up power source in the form of generators so that in case of power failure you don't have to face any downtime.
As dedicated server is big, it generates a lot of heat so proper exhaust system is required to extract the heat out and a cooling system which maintain room temperature. In data centers server rooms are designed in such a way so that a cool air enters in the room from the front and take out heat from the back. Because of cooling system humidity increased in the environment which might damage your server equipments, that's why data center perform all necessary measures to keep the environment stable.
Security of a dedicated server is a prominent feature that's why people adopt it. Data centers ensure server security by installing anti-virus, anti-spyware and configure your firewall settings properly to protect the server from unauthorized access. As far as physical security is concern only authorize personal can access the server room.
Another benefit of housing dedicated server in data center is that they monitor your server 24/7 which ensures you maximum server uptime. If by any chance your server goes down they'll resolve the issue immediately.
So if you are looking to obtain dedicated server hosting make sure your host housed its servers in reliable data centers.