Public or internal app
An in-house application open only to company employees has a different set of requirements than a customer application distributed in the store (MDM, VPN, access policy). Saying in advance which model you choose specifies the development path.
Web + app together
Sometimes a responsive web is enough in the first stage; then the app is added. On the contrary, the app is the priority for marketing. the web can remain presentation-only — both scenarios are discussed.