It saves so much time to just pull down the repo, run "docker-compose up" and have everything running, almost exactly the way it's running in production. With the right node or php version, databases, Elasticsearch, Redis etc.
Just deploying changes affecting both assets carefully in production can be quite awkward relative to a code-only deployment. You might need to do this in several stages, updating your code to allow for but not require the DB changes, then updating the DB schema, then maybe updating existing DB records, then at least one more round of code updates so everything is running on the new version of the DB. And you might need to make sure no-one else on your team is doing anything conflicting in between.
Doing the same in a staging environment isn't so bad because you're running essentially the same process. However, for a development environment where you want the shortest possible feedback loops for efficiency, you need to be able to spin up a DB with the correct schema, and possibly also with some preloaded data that may be wholly, partially or not at all related to controlled data you use to initialise parts of your database in production or staging environments.
It is not always an easy task to keep the code you use to access the database, the current schema in the database, and any pre-configured data to be installed in your database all in sync, and to ensure that your production, staging/testing/CI facilities, and local developer test environment are also synchronised where they should be.
It kind of amazes me that there doesn't yet seem to be a way of handling this in the web development community that has become a de facto standard in the way most of us look at tools like Docker or Git these days.