is dex actually useful?
it sounds fantastic hence i suppose there is a catch
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.
This is a ridiculous take. Samsung is the entire reason Android didn't go the way of WebOS and Windows Phone.
Samsung had pressure-sensitive pen support on Android 5 years before iOS. Samsung DEX desktop environment can turn my phone into a proper work machine with just a USB-C display cable and a lapdock.
They've also had folding phones that can turn your phone into a tablet for several years, but I suppose we'll need to wait until 2030 when Apple launches it "the right way" to recognize it as an innovative form factor.