Normally? Decor, slow release of liquids(water typically), toys.
https://www.pinterest.com/search/pins/?q=waterbeads&rs=typed&0=waterbeads%7Ctyped&remove_refine=water%7Ctyped
They can be scented, glow, water plants, be a toy, be used in decor, but you only ever see them used in one sort of container or another. Was thinking someone using them for their plants might have noticed something.
Personally I was thinking to make items with them that change when wet(or at least don't involve a container).
'Berries' on a painting that swell after a storm.
A Dream Catcher whose beads can change size.
That sort of thing.