We use Vagrant because we do cross-platform development, and because many of those that use our code are on Windows machines. Vagrant doesn't take over the network stack like Docker does, nor does it force us to use Hyper-V. It also allows us to spin up windows machines if needed.

Ultimately our environment is one based on virtual machines, so Vagrant just made way more sense than Docker Compose for us, even though much of our automation code is run on Linux.