It was before my time, so I can't say with any certainty. They were having issues with database performance as the system scaled, and the decision was taken at

It was before my time, so I can't say with any certainty. They were having issues with database performance as the system scaled, and the decision was taken at the same time to switch from a monolith to a microservices architecture. Easier to scale out than either a cloud based or on-prem database possibly?