Half-full wash for CREASING or for CLEANLINESS?

Can any specialists in this forum advise on the advantage of using a half-load rather than a full-load?

My friend and I each have a front loading Bosch washing machine. I put less clothes into a semi-synthetics (polyester cotton) wash than I do for a cottons wash. I seem to recall reading this advice in the instruction booklet and also on detergent boxes.

I am staying with my friend and I notice she puts in a FULL load of clothes for a SEMI-SYNTHETICS wash. She says the full-load is better than a half-load for semi-synthetics because they rub more against one another to give a better wash.

MY QUESTION: Is the advice to use a half load for semi-synthetics is aimed at minimising CREASING rather than aimes at getting a CLEANER wash? In other words, if all we want is clean clothes then is it ok to use a full load for semi-synthetics?

Hope you can help.

Smarko

PS: I understand a machine loaded beyond its full capacity (such as 5kg) may not clean properly but in this message I am taking about a half-load versus a full-load without going above what the machine is designed for.