Perhaps your engineering team favors the workflow of a particular PHP framework. Perhaps you've estimated that for a particular project, it might be worthwhile

Perhaps your engineering team favors the workflow of a particular PHP framework. Perhaps you've estimated that for a particular project, it might be worthwhile to leverage the talent and effort that's been poured into HHVM. Perhaps you've had continued success solving a certain type of problem with a particular PHP library or tool. Perhaps you are constrained by regional availability. Perhaps you're interested in building a product or tool that you intend for your customers to deploy themselves and you want to provide them with the simplest path to accomplish that goal. Perhaps you're building a complex SPA or an otherwise JS heavy application that only requires a simple back-end, and you want to focus your big bucks on attracting quality JS engineers while choosing cheaper PHP engineers for the relatively simple CRUD API component.