Word has been quite good on the iPad for a long time, but I use OneNote far more than Word these days. OneNote is great on the iPad. Excel is more of a challenge to use on a touchscreen device, but doable. I open Excel frequently in meetings so I have some data to refer to, but if I need to do quite a bit of editing or data manipulation in Excel, I’d rather use my desktop computer.
As others have said, the web based versions have more features, but the app versions offer convenience and ease of access. The desktop versions still have the most features, but Microsoft has been steadily improving the Web apps to the point where the differences might not be obvious to the casual user. Outlook is one application where the Web version has surpassed the desktop version in some ways, but still lags in others. OneNote is now primarily a Web app with the option of apps for Windows, MacOS, iOS, and Android.
Excel is tops when it comes to spreadsheets, there are many alternatives to Word depending on what your final products are. Our Office environment uses OneNote far more than Word these days. There are also many mobile centric word processor and note taking tools, including Google Docs, Google Keep, Simplenote, Evernote, Notability, and more. Just depends on what your needs are, but personally Word wouldn’t be my first choice unless I’m in an Office 365 environment where that is expected. Even then Word would be my second choice behind OneNote (which can export to Word).