It’s a lightweight OS, Chromebook are more or less like the new age netbooks. They cover the basics like net browsing and the new Chromebook plays Android apps too but that’s all about it. You can’t run more complex softwares and games like you do on Windows 10. Chrome OS was never meant to be a full fledged desktop OS, so there’s no point in comparing them to Windows 10 powered laptops, not to forget that many Chromebooks are way cheaper than Windows 10 laptops.
They target a two different categories of customers.