First, establish which problem the digital guide should solve. Do visitors struggle to understand the context of the exhibits? Are language versions, audio or a family route missing? Does content quickly become outdated? Or does the venue want to stay in touch after a visit? Each of these needs leads to a different product scope.
Simply having an icon in an app store solves none of these problems. It is like ordering a beautiful display case before deciding what should go inside it. Start by describing how people will use the solution, the content and the team's workflow, and only then choose a tool.
The right question is therefore: "What is the simplest way to give visitors the right story in the right place, while enabling our team to develop it further?" Your own app is one possible answer, but it should not be the automatic choice.

