According to the article, Nobel Prize-winning economist Paul Krugman criticized Elon Musk’s plans for the cryptocurrency Dogecoin, stating that they “don’t make sense.” Krugman expressed skepticism about Musk’s ability to transform Dogecoin into a viable payment system, citing the inherent limitations of cryptocurrencies in terms of transaction processing speed and energy consumption. He argued that traditional payment systems like credit cards are more efficient and environmentally friendly. Krugman also questioned the need for a “Dogecoin to Mars” system proposed by Musk, suggesting that it would be easier to use existing financial infrastructure. Overall, the article highlights Krugman’s skepticism towards Musk’s ambitious plans for Dogecoin and cryptocurrencies in general.