Wishful thinking. But, I think, US is not first in this regard. Sale of grocery against Crypto has already taken place in Europe. Moreover, we now have almost all the gift cards available for Crypto. So, you can indirectly use Crypto for groceries.
Indirect usage can never substitute the direct usage. In indirect usage, what you are doing is that you first convert your cryptocurrency to fiat, and then use this fiat currency for shopping. Here the payment is being made in fiat currency such as USD or EUR. It is not too bad, as the users are being given multiple options. But in the end, you are only purchasing the gift card for Bitcoin and you are not doing any shopping with cryptocurrency. It is just like using stablecoins such as USDT and PAX USD in the exchanges. They are being used as a substitute for USD and not as an equivalent of Bitcoin.