In my opinion (I work at said company) the best thing about the monorepo is that 1 feature that touches several parts of the infrastructure can be in a single PR, and therefore is much easier to review.
This. Where I work it's common for features to involve 3-4 repos and it makes testing and deploying a huge pain. This leads to people sticking code in the wrong place as a work around, defeating the purpose of splitting the code into services in the first place.
