This Supreme Court ruling is exceptionally cruel (death penalty)

I recently read this CNN op-ed detailing a recent Supreme Court ruling that will put Russell Bucklew to death by lethal injection, despite the fact that his lawyers have argued he could suffer an incredibly painful and torturous death of convulsions and choking on his own blood given a medical condition he has. The article goes on to criticize the Supreme Court, specifically its conservative justices, for allowing this ruling to pass, and later on delves into the controversy of the death penalty as a whole, stating the United States is in the company of some of the world's worst human rights abusers. There are many cons with the death penalty detailed in the article, like the fact that it is costlier to taxpayers than life in prison, has not been shown to deter violent crime, and is often inaccurate (meaning you're ending an innocent individual's life) among other issues. It's evident the author of the article has very strong opinions on the topic, however, I'm curious to hear about what others think.

Should the death penalty still be used in the United States? Why or why not? Are there specific cases in which the death penalty should be allowed versus others? Should Russell Bucklew be put to death by lethal injection? Or is that cruel and unusual punishment?