Dropbox has updated its Windows 10 app. It's now a Universal Windows Platform app, with a mobile version promised soon, and it takes advantage of a number of features new to Windows 10 that weren't possible for Windows Store apps in Windows 8.

The Dropbox app allows you to (optionally) specify a passcode that has to be entered before it'll show your files, and this leads to its more exciting new feature: Windows Hello integration. While Windows Hello is so far mainly used for biometric authentication—the facial recognition used by the Surface Pro 4 and Surface Book or fingerprint recognition in a range of laptops—that's not the full extent of it. There's a corresponding API that allows applications on Windows to tap in to the same biometric infrastructure. Instead of a four-digit PIN to reveal your files, the Dropbox app lets you use your face or finger.

It also has interactive notifications for invitations to shared folders that allow those invitations to be accepted or rejected from the notification itself.

More broadly, the app shows how the UWP is much better than the old Windows 8 app platform. The Dropbox app shows this in a couple of ways. One, it supports Jump Lists, the custom menu options that you get when you right click an app on your taskbar or pinned to the Start menu.This is a minor thing, overall, but it touches on one of the sore points of Windows 8 that had many enthusiasts annoyed. Jump Lists were introduced with some fanfare in Windows 7; Windows 8 not only wasn't very good at showing those Jump Lists (since the Start screen offered no way of seeing them), it also had no way for modern style apps from the Windows Store to even use them. Only traditional desktop applications could offer them.

A second is that it supports drag-and-drop; you can drag a file from Explorer into the app in order to upload it to your Dropbox account.

Overall, the app tries to be a good citizen, taking advantage of platform features when and where it can. In cursory usage, it feels like a well-assembled application, and I like that it leverages platform features when and where it can. But I don't see myself using it with any regularity, because it's still a sandboxed UWP app, and that's its big problem.

I use Dropbox daily. It's an important service to me, and having a good client is valuable to me. But I use the desktop client, not the UWP client, and I will continue to use the desktop client because it works better. The desktop app can, for example, sync all my Dropbox files locally and automatically. My hard disk contains a full replica of my Dropbox files and any changes I make to that replica get pushed to the cloud automatically and transparently. The UWP app can't do this. If you want this kind of syncing, the UWP app tells you to install the regular desktop app.

I suspect that this is because the UWP app still has to operate in the sandboxed world. The desktop app has free and unfettered access to my hard disk so that it can sync all the files in my Dropbox folder; sandboxed apps do not. The desktop app can also start automatically every time I log in to get on with the job of syncing without me having to think about using the app. Moreover, the desktop app doesn't merely allow drag-and-drop with Explorer: it lets me use Explorer for all aspects of Dropbox file management, since all the files are synced locally.

The Dropbox app's drag-and-drop is also a sticking point; it only goes one way. You can drag files from Explorer to Dropbox to upload them, but can't do the reverse to save them locally.

What I'm left with is a nice app that shows the awkwardness of the app model. I look forward to having the same app on my phone, because my usage of my phone is different: I don't want everything synced, I want to pick and choose individual files, and that's what the Dropbox app is actually good for. But on my PC, I don't really want an app. I don't want a special destination that I have to go to in order to do special Dropbox things. I want a service, an extension of my existing workflows that seamlessly extends all the existing places and works quietly and invisibly in the background.

And right now, it seems that UWPs aren't able to do that for me.