Lots of people require basic level functionality. Often one or more lists with a few columns and some adding up. Spreadsheets designed for serious users are not very good at that. As you need data integrated into other things not separated in another application. More than 1 list is a pain as you can't move them freely as cell sizes must line up so they mess the other one up. They can't be overlapped or separated easily. Most users are not finance wizards. But the world of open standards is so screwed up that there is no decent way to handle information. Silos are to be avoided too. So it's hard to find an alternative to suffering using the wrong tool. Microsoft doesn't care about users. And open source is focussed on the IT side and not on users.