Companies, businesses, and people in general tend to use the right tool for the right job. In author's case, it was rather simple I would say: they have acquir

Companies, businesses, and people in general tend to use the right tool for the right job. In author's case, it was rather simple I would say: they have acquired an extensive experience in D language and saw its potential by switching from PHP for good. Could they have used swoole and go fully concurrent and asynchronous with PHP, while maintaining their legacy system? Yes. Could it perform? With swoole, they could outperform Golang under specific use-cases and circumstances. But that's not author's point. Their point is, they have used a language and have saved a lot of money for their business. Could they have done the same with PHP? I cannot say, I do not know; what I do know though is that a static typed programming language is ideal for writing performant code, especially for businesses that deal with ads, marketing, FinTech, Banking, and Medical systems to say the least.