I tend to agree with the parent comment, a small team can get away without it if the software stack is stable. PHP 5.2 to 7 is quite a change and should have been documented upfront. I assume that the project must conform to certain software requirements. On the other hand, npm is full of surprises.
I don't disagree that if you can get away with just a local development environment that it is likely easier to get up and running. However, it requires good documentation of project dependencies and discipline by the team to not accidentally upgrade their version of PHP without telling anyone, both things that are easier said than done. Vagrant lets you codify that through "code". In the case of my employer, it's a necessity, but obviously everyone is different.
