Deaths per million population is indicative of the effectiveness of the entire country's response to the pandemic (and on how early or late they were affected - the USA may be 10th by this measure but they're catching up fast to other countries that were affected sooner).
Deaths divided by confirmed cases is subject to the vagaries of how effectively the country is testing and inconsistencies in testing protocols. For example, how can Qatar have 115,368 confirmed cases out of a population of 2.8 million and only 193 deaths? It's great that they've had "only" 193 deaths (69 deaths per million population, 0.16% of confirmed cases) but how can there be so many confirmed cases? They've tested about 20% of their population, which is good, but their numbers aren't consistent with the rest of the world. Either Qatar has been extremely good at finding every infection (but then, why do they have so many if they could contact-trace and isolate every infection?), or they're getting a lot of false positives and not filtering them out ... which is my guess.
India has 2.6 million confirmed cases and 51,000 deaths. Do you believe either of those numbers?
Yemen has 1869 confirmed cases and 530 deaths (population 30 million). They're not testing. (Total tests 120)