All the built-in collector types use SSIS packages to collect and upload data, but you don't have to install SSIS to make them work.

Looking in the installation folder of SQL Server, I see some tasks DLLs. The "Execute Process Task" is not there.

I suppose that the tasks needed for the built-in collectors and the maintenance plans are installed with the "database engine" components, while all the other tasks are installed only with the SSIS components.