Not whimsical at all. I haven't used the app for about a year and a half. I gave up on it after multiple updates didn't fix the numerous problems.
There is no need for an app. For recipes, Google leaves the app for dead. For setting the temperature, the scroll wheel gets me there quicker than the app. For the timer, it's easier to just set an alarm on my phone. I'll hear that alarm even when I'm outside, it doesn't require a working bluetooth or internet connection, and I can set it in a fraction of the time it takes to set the timer with the app.
The app adds essentially nothing except complexity and lots of extra failure modes. Just say "no", and your life with the Anova will be much happier.