Excel is so powerful that people are doing with it stupid things and than their businesses rely on them. That stuff will never work in Docs.

Office is a killer product, with extremely rich feature set that works very well. Sadly, there is nothing in the market that even close. It is the main (perhaps only) reason I still have to use a Windows VM.

For detailed and powerful spreadsheet use there is nothing that compares to Excel. This coming from someone forced to use Google Sheets at a former company, after having Excel.

As much as it pains me to say it the power of excel is uncomparable, especially for people who can’t program and are never going to learn how.

For me, a common use case is to receive a large document from someone using MS Office, make small alterations or comments, and send it back... while being certain that I have not changed anything else (including formatting and layout of included illustrations) that I did not want to change. Neither Google Docs nor OpenOffice currently support that, simply opening and saving a nontrivial Word document changes the layout.

But, a lot of people are forced to use office for various reasons - trying to edit a docx in Docs/Pages/LibreOffice, for example, can be really frustrating for any number of reasons (fonts, margins, etc. all sometimes break spectacularly).

So if you're using office quite frequently, windows can be very appealing.