It's a lot different when you're working with certain teams of mixed technical aptitudes. An automatically assembled VM image I can distribute means much less time supporting our less technical members of the dev team (front-end, designers, biz dev guys).
If it's just you, absolutely, don't bother. But it gets much more difficult to support a variety of platforms and configurations as your team size grows. This is where vagrant+chef/puppet really shine.
> An automatically assembled VM image I can distribute means much less time supporting our less technical members of the dev team
Absolutely. At my previous work we had 'standard' VM with all necessary tools such as Visual Studio 97. I just dont understand if it brings so much benefits if all you just need is different version of Ruby.
If it's just you, absolutely, don't bother. But it gets much more difficult to support a variety of platforms and configurations as your team size grows. This is where vagrant+chef/puppet really shine.