some people don't have the skillz to run a dedicated server, ... although it does give you lots of flexibility.
i use both services.
i run game servers off a dedicated box, however i can't depend on myself to keep a server up all the time, so for sites which are important, such as this one, i use
www.vilitas.com . by far the best up-time i've ever experienced with any hosting company.
for the game server, we own our own and just co-locate it though. only $100/mo for 1000gb of traffic.