HCM and ECC 6.0 - Conversion to business partners BEFORE upgrade to S4/HANA

I've studied the SAP notes but I'm having trouble finding information on the conversion of employees to business partners.

All the suppliers / customers can be converted to business partners in ECC 6.0, which is recommend due to errors and so on, so this is recommended before the conversion to S4/HANA.

Is the conversion of employees to business partners a necessary task in ECC or not?