I'd leave it as is. If you actually use that fireplace, the hearth is going to get a lot of wear and tear. Your paint will chip early and often.

You have the original no maintenance finish with the bricks. I'd keep it.

Or tear it out and redo the whole hearth. The fireplace picture attached look very similar...except the previous owners painted the hearth..looked terrible, soot wouldn't wash off, bricks were chipped and cracked... We lowered the hearth and repoured concrete to bring tile to the level of the hearth, parge coated the surround and tiled over it, inlulding the Heatilator vents.

I had white painted bricks that I painted with Benjamin Moore chalk paint, I think the color is baby seal. Anyway a dark gray. I love the effect