Another way to make tires more expensive. Don't expect to see this on the market any time soon. It will never be more than a novelty.
The military (H1) Hummer has featured a "Central Tire Inflation System" for a long time, that can inflate tires on the go, without requiring the purchase of special tires. But you don't see that system on other vehicles, despite its utility, because for normal civilian use, it doesn't add enough in terms of safety or convenience to justify the expense.
I suspect self-inflating tires will be the same.
Engineering: Finding complex solutions to simple problems you didn't even know you had.