Choose around user behaviour
A web product is often best when users need broad access, admin control, dashboards or workflows at a desk. Mobile becomes stronger when the work happens in the field, on the move or through repeated quick actions.
The right first platform depends on where decisions happen and how often users return.
Consider workflow depth
Complex setup, reporting and management tasks usually benefit from a larger screen. Short approvals, status updates, tracking and notifications often work better on mobile.
Many products start with one platform and add the second once usage patterns are proven.
Plan for shared foundations
Even if the first release is web-only or mobile-only, the backend, permissions and data model should be designed with future channels in mind.
That keeps expansion practical instead of forcing a rebuild when the product grows.