Quite a lot of the time you see people buying something ridiculously expensive with EBT (e.g., lobsters, high grade steaks, etc.), chances are they're selling it at a steep discount, and then taking the money from that to buy things EBT doesn't cover. Some particularly enterprising grocers will be the same ones selling and buying it (and selling and buying it, and selling and buying it) from their EBT patrons.
Having EBT cover junk food ultimately reduces this systemic fraud, waste, and abuse, because rather than buying $50 worth of lobster, to sell for $30, to buy $30 of crap calories, they can just buy $50 of crap calories directly. It's also pretty easy when you're seeing your man to fence your EBT lobsters to see if you can pick up some drugs since you're already there. Eliminating the necessity of the first transaction, reduces the opportunities for the second transaction. I suppose there's also some small fraction that were able to fool themselves into believing they were doing it to buy the foods their kids wanted, but funnily once it's all the same cash in their pocket they have enough for cigarettes and booze again.
In any case, regarding the woman in the CostCo EBT video, she confesses to committing entitlement fraud a couple times, so if she can be identified it sure would be a shame if someone were to make the relevant authorities aware of her illegal misappropriation of benefits.