Honestly these stores add a layer of functionality to Japanese life (along with vending machines) that increases QoL much beyond reasonable expectation. They have become a bit of a meme, but it's one thing I really miss from my brief time living there. They add affordable right-around-the-corner convenience to every situation, and that you would have to be much more wealthy in another country to expect.
In the US it is an obvious choice to not waste your money at 7-11. The gas is more expensive than Sheetz usually, their hotdog like products and terrible pizza have been sitting under a heat lamp for more than a day. And every product there is cheaper elsewhere. But 7 and I holding still is much better.
But it's not actually good and just seems like an extremely easy opportunity for the parent company in the US.
All convenience stores in the US are basically terrible except for a few who specialize in super clean bathrooms on road trips and a few north east places that capitalize on the fact that the region produces the best subs in the world. Really feels like 7 will have a Nintendo moment at some point and actually care about profits outside of their home country one day and just clean up.