Bark mulch breaks down, over the course of a season, and decomposes into humus, that good black soil, full of life, that we all strive for as good gardeners. When we plant, we dig this humus into our planting holes, mixing it with our not so good clay soil, lightening and improving the clay. But if you want to plant an area with shredded rubber mulch on it, you'll wind up digging rubber into your planting holes. I doubt you'll attract any earthworms, beneficial insects or beneficial bacteria with that. The presence of humus among mineral particles and air spaces enables soil to nurture plants two ways.
Humus creates a loose structure that simultaneously holds moisture and drains well.
Humus also creates an environment that supports living organisms that convert soil nutrients into a form plant roots can use, building soil fertility. In short, humus bring soil to life. It takes organic matter to have humus. Humus is created by the decay of debris, which as the Lowe's release says, can be smelly. Organic matter such as leaves, dried plant parts, prunings, animal remains, manures and other debris is routinely removed before it can recycle into the soil.