The Salesperson role seems to be a license-based role, so it is automatically assigned to users in same tenants with certain licenses.
Due to this issue, new licensed user will get access to multiple applications/instances on that tenant without explicit role assignment. Considering OOB Salesperson role is having BU or Org level access in many OOB entities, this can cause sensitive data exposure issue if other applications are using custom role with restricted access control (e.g. basic / user level privilege on OOB entities) and would like to maintain restricted access for limited users.

Regards,
Kunal Murarka