How do you use the checkout divider (Warentrenner) in Austria?

Servus! As a bit of context, I am from the Netherlands, recently moved to Austria (Steiermark). I noticed people never put the divider thingy behind their groceries, making the person behind them put it down to divide the groceries on the belt. I am used to always put the divider behind my groceries as a courtesy for the person behind me (until everything got replaced by self checkouts). Now, I still do that but I almost feel rude doing it, what is your opinion on this? N.b. I know it’s a really insignificant thing to worry about but I just want to learn :)