What value stablecoins settle? Go to any supermarket in the world and you'll see people paying with Visa or Mastecard every single minute. But where are the stablecoin payments? I never encountered a business, even a small one, that accepts stablecoins.
My guess is that most of the activity on stablecoin network is speculative trading, especially by bots. If someone shut down stablecoins tomorrow, the world wouldn't notice. If someone shut down Visa tomorrow, that would be Armageddon.
You have said it all, I have not seen any super store or boutique that has accepted stablecoins in anywhere but I have seen bitcoin being accepted in the city mega stores. People have not confident on stablecoins. Even online shopping people use verve, Visa and Master Cards. Stablecoins are not reliable because their value is not even appreciated. Any business that is accepting stablecoins as their payment methods is on their own risk.
Stablecoins is just like airdrop. I am not advising anyone or business owners to accept stablecoins in their payment methods of goods and services. Because they might lose all their money. Stablecoins are centralized projects which can be collapsed at anytime.