There is a lot of debate over natural play, the benefits vs risks of natural loose materials as impact attenuating surfaces, and the high cost (environmentally and financially) of rubber wet pour. But what do we learn from all this? I think that although as play design professionals we are coming from differing professional and personal experience our common ground is that we all aim to help build happy, healthy, confident children.
Depending on the community we are designing for shapes their needs and our design response to those needs. Sand has excellent play value - which is why kids love going to the beach. Older kids make use the sensory mass to lie on the warm sand, run and fly kites, build sand castles, dig trenches, build whole cities, bury their little brothers, collect shells and feathers. Young ones squish sand between their stubby toes; pour it endlessly from one bucket to another. However, sand does compact and I broke my back falling onto wet sand (admittedly at speed and from a height, off a horse), so it wasn't so much fun then. I was lucky. I can now walk.
I do not believe the choice of IAS is an all or nothing situation. It is possible to introduce nature through playable planting into a wet pour environment, to further soften the hardscape. (‘Sand’ coloured wetpour under high equipment with coastal grass planting on artificial ‘dunes’ has been done) It is also possible to provide community-sized sandpits, and climbing areas, but not necessarily on top of each other. In tight funding situations we need to look at play value for money spent. If a community need high climbing opportunities, some of the money will need to be spent on IAS. In a multi-generational play setting it may be more appropriate to provide a giant sand pit, with a few swings to one side.
It all comes back to what does the community really need and, working within local parameters, how can we best meet that need? (note, this is often quite different to what they think they want!)