Do they shrink and swell in the soil, as the soil gets drier or wetter?
If they do, it might be a way to keep some outdoor raised bed clay soil aerated: like freeze-thaw cycles expanding water to create voids or air spaces.
It's too bad that they swell when wet instead of swelling when dry: over-watered soil needs extra air channels more than dry soil.
But for marginally over-watered soil, maybe these beads would pull enough water out of the soil that some air could re-enter. In other words, they might increase the amount by which you could over-water without drowning roots.
I recently saw a "broadfork" demonstrated as a low-till way to keep soil "open" without turniong it over and exposing new weed seedfs. I like that idea too.
But having little plastic pellets loosen the soil for me every time it rains sounds cool! Like little ballons.