Babaganoosh: I agree partially... it's very good for testing and experimenting, it's not bad for learning... just using Vagrant for running boxes, and you can have a look at what goes well with what, how things look when configured properly
For example some boxes were a great help when I was learning about nginx...
as well if you're configuring server one time, it means that maybe you'll need to do that in future, why not have ready/quick setup? If I use it I can pretty safely try out new hosting providers without worrying too much... I know it might be a lot to a person just starting with administration, but I'm a self-taught in 99% of stuff I do and I nearly pissed myself from happiness when I discovered it :D I fucked config again? no problem, reprovision ;)
and you can have it running within hours, even to use as a local dev envoirnment and even if you dont know nothing about it.