SSIS Installation on Dedicated Server

We are planning on installing SSIS 2016 on a new dedicated ETL server. The packages will be called from SQL Server Agent (on a separate server), or from an application (again on a separate server). From reading the Microsoft docs , it seems that we need to install **Database Engine** along with Integration Services on the dedicated SSIS server. Is Database Engine required on the SSIS server for our needs? I'm confused by this: "*If the ETL server does not have an instance of the Database Engine, you have to schedule or run packages from a server that does have an instance of the Database Engine*". Does this also mean that the SSIS server is then redundant if run from a server that does have DB Engine?