Is a black asphalt roof a practical choice?

All depends on where you live, black absorbs heat, which will make your house hotter in the summer if you have no tree coverage which equals higher cooling costs. If you are in a forrest which never sees sun, might be a good idea. Where I live a light colored or tile roof is best.

Always do a black roof, they by far make a house look much richer. If your worried because it attracts heat. Drive around and look at the houses that have funky colored ones, if you have good taste go black. I live in the east in a very old house and have a shake roof. However, black is what everybody around me has, and I have studied this question for years. Black IMO looks best!

PS just ask a highly qualified heating and A/C about the extra cost it's negligible.

I used to work in a roofing factory and every single roofing tile and roll of roofing material started as black asphalt on a fabric backing material. Colors (mostly in the form of granules) were pressed into the asphalt so that you could then make your house look matchy -matchy with siding, etc. So yes, it is practical as it is water resistant. Asphalt shingles are easy to install, widely available, cheaper to produce, and are the most popular roof material that customers are choosing for their roofs. Asphalt shingles are popular because of the longer life span they have over other roofing materials. Choosing black is a personal choice.