My Skylake iGPU ran everything on my PC just fine for me. That ranges from Minecraft to (apparently the most graphically intensive game I own) The Talos Principle. Sure, not always at the ultra high settings, but that's not something I care about.
Once I upgraded recently to a Threadripper I threw in an old GTX 760 because Threadrippers don't have iGPUs. The 760 also did fine. Now I finally have a bleeding-edge-ish Sparkle Arc A770, but that's only because I wanted to run a shader coding event and didn't want to force other people to care about the server having a behind-the-curve GPU.
Once I upgraded recently to a Threadripper I threw in an old GTX 760 because Threadrippers don't have iGPUs. The 760 also did fine. Now I finally have a bleeding-edge-ish Sparkle Arc A770, but that's only because I wanted to run a shader coding event and didn't want to force other people to care about the server having a behind-the-curve GPU.