the i7 provides little to no improvement for gaming. This may change once DX12/Vulcan become the default for game design and designers uses it properly. But for now the i5 is the sweet spot, you're better off spending the difference on a better GPU.
If you plan to stream while gaming, the i7 makes sense. If you're planning on gaming while really doing nothing else intensive in the background, an i5 is great.
you can see the difference is +/- 10fps, also if the game utilized multi threading then it will scale higher for i7, outside of that i5 is still very viable option
If you are budgeting, or just want o play a game, the i5 is more than enough, especially with the better models.. However, want to future-proof your system for a few years, or oc and get crazy fps, you'll want an i7. Hope this answers your question.