More reach is not automatically better. A message shown to a thousand wrong people can achieve less than a clear flyer placed where the right twenty people pass by.
The choice therefore starts with who needs the information, where that person already looks and how much explanation is needed. The medium follows from the message and the audience.
Look at behaviour and context. A local activity may benefit from a physical flyer and a simple web page; a technical manual may benefit from a well-indexed online publication. A combination often works better than a single channel.
When you can clearly describe whom you want to reach, what that person should do next and how you will assess the result. Without a clear landing page or message, you mostly buy more impressions of something unclear.
Do not look only at clicks or impressions but at what happens afterwards: do people understand the information, do the right questions come in and does the audience fit the activity? Lower reach with a better fit can be more successful.
For digital design, Digital is relevant; for physical design, Visual arts. The emphasis can be on making and understanding together rather than simply receiving a finished file.