Ethanol (alcohol) is like a magnet for water. Ethanol-blended fuel may contain some water.
If it becomes saturated, the alcohol-water mix drops to the bottom of the tank. If it gets pumped into your car, it can cause damage.
That might result in a mechanic's bill of $500, $900, or more (drain the tank & fuel line, add good gas, maybe more).
Speedway (and perhaps most gas stations) makes no effort to continually monitor fuel "quality" (ethanol content, water content, phase separation). Buying ethanol-blended fuel may be a *** If you incur damages because of "bad fuel", don't expect Speedway to make you whole (and don't expect to win in small claims court).