The ROG Swift isn't even close to any average/decent IPS. But if you think you would need G-sync, then it's worth it. However, do note that simply a 144 Hz panel already minimizes our perception of screen tearing. I will tell you why, but I will use 120 Hz as an example, to make it easier to follow. 144 Hz is technically 1.4 ms faster than a 120 Hz panel.
A 60 Hz display refreshes every 16.67 ms, this is because 1 / 60 = 0.0166 (16.67) ms. This means that the monitor picks up the frame in the GPU's frame-buffer every 16.67 ms, meanwhile the GPU draws a frame in the back-buffer. It then copies the frame in the back-buffer to the frame-buffer as often as it can. So should I just get a 144hz monitor with 1ms respond time it would be very hard to notice screen tearing even at 240 fps in minecraft?
Okay, so we know that a 60 Hz display refreshes every 16.67, but why does it tear? That is because the monitor has a set refresh rate, and it picks up the frame from the frame-buffer, at the same time the back-buffer copies it's frame to the frame-buffer.
It's not the monitor that is half finished, it's the graphics card that is half finished and the monitor that is causing it. The monitor has a set refresh rate, again: 60 Hz = 16.67 ms. The graphics card does not.
V-sync, G-sync, FreeSync (if you use AMD graphics--you don't), will stop this from happening. However, by using a 120 Hz panel. What happens is that screen tearing occurs twice as much on a 120 Hz display, than on a 60 Hz--but why is the 120 Hz display better? That is because the difference between 2 frames, is going to be much smaller (faster). Simple math tells us that 1 / 120 = 0.0083 ms. That is indeed much lower (faster) than what a 60 Hz (16.67 ms) display is capable of. Provided you can push 120 FPS in games, though anything above 60 is gradually going to feel smoother and smoother, and minimize the screen tear up to 120 FPS.
This is because the frame that is tearing, spends half as much time as the 60 Hz display, on screen. The result is that it's very hard for us to actually notice the tearing, on a 120 Hz display, in comparison to a 60 Hz display.