Even if there is no additional supply available, there still could be some benefit.

If the price of gas were far higher, people may not fill up their tank all the way and only purchase what they really need. So instead of the first X people getting full tanks and the next Y people getting nothing from an empty gas station, in some scenarios everyone could get a smaller amount.

However, the issue of poor people not having access at higher prices is still a problem. It may be better served by having the government step in to provide each person $Z in gas money (paid for by a tax on "gouging") rather than an outright gouging ban.