If you are a user of Office Online (and I know that some aren't, so please don't rage over this article) and also use Chrome, this could be for you. I also find it advantageous for Linux users who use Chrome and Office Online, since desktop Office doesn't have a release for the Linux platform (which is sad). One thing to note is that these "apps" are just glorified links.
One sad thing to note is that these apps currently do not work offline. If they were available offline, it would be a lot more useful. Either way, installing these Chrome apps will also add them to your list of applications, under the "Chrome Apps" category. I say this because the "start menu" would be referring more to Windows, etc. Here's my Chrome apps list on LXDE:
How To Install
Click the links in the list for whatever Chrome app(s) you want.