wys33 :
Is it worth for me to buy a Asus ROG Swift PG248Q if I currently have a Geforce Gtx 970?
A G-Sync display like Asus ROG Swift PG248Q will help with smooth game play, by helping with tearing and stuttering by matchin GPU FPS and monitor refresh rates.
Without G-Sync, your GPU will render as many FPS as it can but your display runs at a fixed refresh rate, which will create tearing and stuttering.
A G-Sync display (FreeSync for AMD) will run in sync with your GPU for smother game play.
For gaming I think is worth it, but you will have to decide if it is worth the investment for you.