One of the ideas behind is, that we want to provide something using a communication channel people use every day rather than introducing a new one like Slack, Hipchat etc. However, StandupMail is a great addition to teams using those tools already.
Using StandupMail is not about sending in "dones" for every single task accomplished. It's more about a quick recap of what everyone thinks is important for the team to know to stay productive the next day and overlook the big picture of the project.