I have not visited this location yet.
This seems to be the 5th public station built by EWO. It was not mentioned in the list of 4 locations in the Web Archive of May 2015 but is added in the version with 5 locations from October 2015:
In Zusammenarbeit mit der Zentralbahn realisierte das Elektrizitätswerk Obwalden bereits an fünf Standorten im Kanton Obwalden Elektrotrankstellen. Bis auf weiteres können Sie Ihr Elektrofahrzeug an den Bahnhöfen Alpnach, Sarnen, Sachseln, Giswil und Engelberg kostenlos mit «EWO NaturStrom» tanken.
On Chargemap, most pictures show an older innogy charger but there's also one picture of a Compleo charger at the same place. Most pictures show the 2 spots available for the public and others show the Mobility spot on the left. 2 comments from the same user in March 2024 say both sides are used by Mobility, but there are also charging sessions logged in April and May. Comments in March 2022, July 2022 and April 2023 mention the left parking is already for Mobility. The oldest comment is from January 2016.