For a single developer tracking their own work this may be fine, because you can keep the entire spreadsheet and the details of the issues in your head. However

For a single developer tracking their own work this may be fine, because you can keep the entire spreadsheet and the details of the issues in your head. However, this doesn't scale. I recently worked somewhere that used a couple Google Spreadsheet to track around twenty people working on around ten closely related projects. Moving to Redmine, while resisted by the manager types that didn't want to learn new software, dramatically improved our ability to get things done.