Back during the infancy of this software, most people would use it for just two reasons: to store data (especially customer database) and as a glorified calculator. Perhaps because those are a spreadsheets intended or more practical uses or that people are not really that trained to use its features to the fullest. You would even be surprised that up to now there are office employees who, when they are prompted to make some calculations, they would open their spreadsheet software and do the calculations there. However, as weird as that may sound, it is one of the ways that a spreadsheet can help speed things up in the office. Especially if the employee has been working on spreadsheets for a long time that making fast calculations using the cells has become second nature to him. But there are other good uses for this application.
When presenting your business plan to an angel investor you must understand that they will be very interested in your spreadsheets and proformas, but you must also realize that it is typically an entrepreneurial optimistic approach, which causes problems with proformas. Therefore, you should have dueling spreadsheets; that is to say the spreadsheets, which take your best guess and double the time, double the expenses to compete with your optimistic approach. You should be able to present both of these to your Angel Investor; who chances are is a retired business person with a little bit of financial savvy.