I understand why this is, although it's confusing. You can add Adobe's Creative Cloud as a source to the iPadOS Files app, but that gives you access to the "Files" section of Creative Cloud, and not the "Cloud Documents" section, which is where Photoshop stores its documents. Photoshop doesn't support Open in Place, but it would nice if it did. iPadOS includes an Open in Place feature developers can support, which means when something is opened in the Files app, changes are saved in place. You can export as a PSD, JPEG, PNG, or TIFF, but it's clear that Adobe intends customers to see Creative Cloud as their primary storage. However, when documents land in Photoshop, they get stored locally and in Adobe's Creative Cloud. Photoshop happily opens files from the iPadOS Files app, meaning it'll also import from Dropbox and other sources. If your favorite Photoshop feature wasn't mentioned above, there's a very good chance it's not in this version. Layer Effects and Smart Filters aren't in this build, but their spot in the interface exists, and there's some placeholder text suggesting they'll be coming soon. For many customers that won't be an issue, but for those hoping to use it for print pre-press or higher-end photo retouching, you're out of luck for now. There's no CMYK, higher bit depths, or a way to choose color profiles yet, but Photoshop itself notes that they're coming soon. Version 1.0 works in RGB and 8-bit per channel only. Linear gradients can be drawn, but only using the current foreground and background colors - there's no editable stops and no other gradient types. Text can be multi-colored and can use custom fonts via the new font management system in iPadOS. Text and gradients are included but very stripped back. Around half of Photoshop's adjustment layers made it into this version, but Adobe has done a good job choosing the most commonly used types. They offer many ways to brighten, darken, change the contrast, change the color balance, and perform other color manipulations.
Photoshop's adjustment layers are a staple when it comes to making overall image adjustments. I'm in two mindsets about that - do channels only exist in desktop Photoshop because they were created when layers didn't exist? Given a clean slate, would an ideal tool include them? I use them all the time, but I'm not sure if that's due to learning Photoshop at a time when they were the only way to do certain things. There's also no way to directly work with channels or save selections. The selection basics are all there, but advanced features, such as automated selection of people and other selection refinement, aren't in this version. That means many of the standard masking techniques used for photo retouching and illustration are well covered. However, clipping layers to other layers and groups works. Masking is limited to bitmap masks only (no vector masks yet).
The painting and retouching tools are a joy to use with an Apple Pencil. Given the lack of other tools and panels, Photoshop for iPad feels fluid and focused for this kind of work. If you're looking for something that's better in Photoshop on an iPad than the desktop version, using the spot healing brush and clone stamp tool with a Pencil is a great place to start. Custom brushes can't be created or loaded in, but there is a wide range of bundled brushes. The layers panel can also be displayed in a highly compact mode with just thumbnails and no layer names, helping maximize screen real estate, while still allowing access to many common features via gestures. Opacity and blending modes can be set, and the blending mode popup menu includes preview thumbnails - a nice touch that's not present in the desktop version of Photoshop. Layers can be reordered, renamed, moved, resized and transformed as per the desktop version. Most of the layer management and blending options have survived the journey. With that in mind, it's far easier to describe what is there, rather than what's not there. Adobe's description of what's included is bang-on and should be taken very literally.