This viewpoint is 11 km (6.8 miles) from the center of El Chaltén. So, if you don't have a car or can't get a ride, it might not be a good idea.
It's a large viewpoint, with space to park your car as well as improvise benches on the wooden fences. So if something in your planning went wrong and you can't do what you wanted, enjoy the view of the small town and its natural beauty from that point.
You won't regret it.
PRO TIP:
Prepare for strong winds after dark.