Here are my thoughts on this topic.
Some reasons users should consider an Office 365 subscription rather than a desktop client installation are to:
(Home users)
1. Reduce vulnerabilities and risk surface on PC or device.
2. Eliminate the need for re-installation upon re-imaging.
3. Reduce the number of weekly updates and patches.
4. Access MS Office suite from multiple devices.
5. Eliminates need for constant version upgrades. - Big plus
6. Better orient themselves to the software differences if Office 365 is used in user's work environment. This enables users to gain skill confidence to possibly explore more effective and efficient methods of using the application through advanced skills.
(Business users)
1. Above items 1 - 5 increasing network security, user accessibility and productivity, reduce work for IT staff, and create a leaner IT budget. Cloud solution vulnerabilities become the responsibility of the subscription provider rather than the company. Subscription providers often times have better resources to address these issues. This also relieves their clients from needing to increase their software, and expertise expenses to address the issue themselves.
2. It is my guess this would also ease licensing issues.
3. Creates a uniform application environment.
4. Companies and government agencies are constantly looking for ways to securely trim IT fat and centralize resources. IT resources as a service are increasingly utilized in response. Cloud solutions through subscription is one of those services. For companies addressing these issues wishing to continue using Microsoft's products, Office 365 is the better selection.