Golden Shields

Gold is needed for suits and small temp crafts that must enter larger crafts. It provides some protection. You get the secondary effect, yes, but it's better than nothing... better than pure spring water. With low density material you need A LOT of it and sometimes you don't have the room for it, such as inside a suit.

Suits are good for about six hours. Small temp craft habitation should be limited as well.

For large space settlements, go for low density, yes.

George
cygo.com

The assumption seems to be that a radiation shield made of water or
dirt would be very thick (on the order of two metres), while one of
gold or lead would be very thin (on the order of ten centimetres or
so). I can kind of see how a thin shield, even if made of dense
stuff, could generate dangerous secondaries whick don't have to travel
very far and thus make it into the habitat.

But what if your golden shield were a metre or two thick? I'm
guessing that the secondaries problem wouldn't be a problem in that case.

Having said that, I don't really know, and am prepared to be wrong on
this.