Any tablet can already create documents and spreadsheets, surf the internet, check e-mail and calendars, access social networks, edit movies, Skype... Everything that %95 of the population needs. People that need higher caliber tools (developers, creative professionals) can afford another system.

So Windows needs a stronger reason to exist it's going to dissuade the average consumer from buying either the market leader (Apple) or the cheap alternative (Android). Android is the real threat. A $200 PC replacement is quite feasible within a year and really deals a blow to Microsoft's business model.

For consumers its less clear. Maybe XBox Live.

Any tablet can create spreadsheets, but not as well as Excel. Any tablet can create a document, but not one that's going to be 100% compatible with the version of Word they have on their desktop PC. Those are all very strong reasons to buy a Windows Tablet.

Sarcasm aside, a lot of people still use Office. Far more than use Google Docs. Even businesses that are using Google Apps for e-mail still use Office for their documents. Being able to edit documents with 100% reliability on a tablet could be a big deal when it comes to corporate tablet purchases, for a start.

"Microsoft’s average revenue from its Office suite licenses sold to enterprise and retail customers has been declining due to competition from cloud-based app providers like Google, Amazon and Salesforce.com, and also due to increasing lower priced products sales in emerging markets."

There are still a ton of companies out there that use office. Creating a Windows Tablet could well cause sales of Office to increase.