Great point on the value of keeping tabs on timing. Most of us are very busy and many are fortunate enough for the job hunt to be part time. Having a clear idea of when the last time you had contact with a company is exactly the type of thing we are trying to make fun and easy.
I just forget what the status of each application was or is. When did I apply, when was the last communication and what was discussed. I just don't want to worry about any of it, so I write it down.
I wouldn't use an app like this because I would simply create another spreadsheet when I need it again, but I can see how it would be useful even for a small number of companies to track.