Without at least the most obvious astronomical observations and rudimentary astronomy, our forebears would not have been able to determine the right time of year to plant or harvest their crops. The fact that they were able to do so was a survival imperative, without which smaller, scattered human settlements might never have been able to successfully increase their food supplies, and might literally have starved to death. One of Magical Realist's ancestors might have been one of those who perished.
The Aztecs sacrificed a human each day to their sun god Huitzilopotchli. Otherwise, the sun might not rise. They probably didn't value astronomy very much, but they did have a fairly good calendar. Modern calendars even throw in a leap second every 400 years or so. If they did not, eventually summer would happen in January. Likely no one would even remember why it shouldn't be. Granted, there are a lot of seconds in six months. Eventually, the calendar would straighten itself out again. Even a broken clock is right twice a day.
Without extremely refined observational astronomy the way we are able to do it in the 21st century, we could not receive early warning of incoming asteroids before they strike the Earth, or even predict where large chunks of space debris from rocket launches and satellites will be when we launch more, to say nothing of warning us about solar flares that might affect the operation of telecommunications satellites valued at tens of millions of dollars, facilitating communications on internet connections like this one, among other things. If Magical Realist believes this part of science to be of no value, well that's just a shame.
Astronomy is useful. It is philosophy that consistently fails the test of being useful in any way. And it's been that way for millennia.