"电脑不如手机有用" 的英文表达是 "computers are not as useful as smartphones".
来源：这句话来源于对比电脑和手机在日常使用中的优缺点。相比较而言，手机更方便携带，更易于使用，而电脑则更适合办公和处理大量数据。
例句：
"I find that my smartphone is much more useful than my laptop for everyday tasks." (我发现我的手机比我的笔记本电脑在日常任务中更有用)
"Smartphones are becoming increasingly more powerful, and in some ways are replacing the need for computers." (智能手机变得越来越强大，在某些方面正在取代电脑的需求)
"While my desktop computer is great for working on big projects, I find that I rely more on my smartphone for quick and easy tasks." (虽然我的台式电脑非常适合做大项目，但我发现我更依赖我的手机来完成快速简单的任务)