Yes it is. Floating window support makes a big difference for actual multitasking. In Dex you can also drag and drop files and images, which is not supported on Android. Considering that you can use Termux for web dev work, with a proper desktop environment, it becomes an actual computer instead of a locked down Google Docs type of device.

The catch with Dex is that it's only offered on the high end models: Galaxy S and Galaxy Z Fold series phones.