There was a time when HVAC consulting engineering firms had a stand-alone HVAC department with a registered professional engineer as the department head.
Quite often, design engineers choose decentralized HVAC systems because of first-cost benefit, packaged equipment, simplicity of design, and the repetitiveness of the installation, to mention just a few of the features.
Recently, a much younger engineer than I asked if we could meet and discuss an energy retrofit project she was working on but was not familiar with the application.