for PCI Express 2.0 x16

My current motherboard supports PCI Express 2.0 x16.

If I buy a new video card 1050 TI PCI Express 3.0 x16, would that be a waste of money since my current motherboard cannot get the maximum benefit from the video card? If yes, then which video card series should I get? How about the 730 series: https://www.frys.com/product/8879232

I am getting a new video card because I will be getting a 4K monitor.

Also, the higher the refresh rate and frame rate is the better right?