if you can use a existing engine and not wast resources on all the things which are not the main selling point and in turn spend more resources on getting the main selling point right, why should you not do so?
AFIK few, probably non of the more successful established game engine force you to use their physics engine
developing games is cost and time constrained
if you can use a existing engine and not wast resources on all the things which are not the main selling point and in turn spend more resources on getting the main selling point right, why should you not do so?
AFIK few, probably non of the more successful established game engine force you to use their physics engine