I agree the graphics card is overkill.
If it makes you happy, do it. No point building a system if you aren't loving every aspect of it, imo. But the editors of a gaming computer website wrote an article I just love that summed up the obsession with really pricey big graphics cards. They wrote...
It doesn’t matter to me whether I get 30 frames-per-second or 130. As long as the game plays smoothly, all the extra fuss for more frames that I can’t see anyway seems superfluous.
So if you want to save some dollars, don't overdo it with the graphics card. I personally couldn't advocate anyone buying a card worth more than $250USD. You are just dipping into pointless luxury then.
BUT if you can afford it and you want to secure your gaming experience for years to come, sure, why not.