Currently neither Eevee nor Cycles support Hemis like they used to work in Blender Internal. One engine falls back to point light and the other to sun light respectively.
But maybe they shouldn’t be supported like in Blender internal either. Hemi lights are an oddity of old engines but nowadays we have a better understanding and better models of the sky light Hemis were trying to fake. We have image based lighting, hdr, background nodes, pbr cubemaps, we can even use the Sun with a very big radius
That leaves two options.
1: They should be removed, including the button, the icon, the menu option. Less code to mantain, right?
2: They should be upgraded to work better with the background, maybe automatically adding a sphere gradient to the background, or multiplying the intensity of that area of the background by X amount, with different gradient and radius options. Compared that to using nodes to create half domes of light, which isn’t the most friendly thing
I personally prefer for it to be removed