This was a very affordable deal to many, like myself. The next lowest price to buy Energy with a credit card is the $9.95 4025 deal.
Sure, it's about 100 CE/$ more, but ask someone, if they would donate $2.45 or $9.95, they'll more than likely go for the cheaper option.
From a business standpoint, having a lower priced deal like this can help OOO's bottom line as multiple purchases of the small deal will be notable. Many players may just blow through the first $2.45 and decide to purchase another. A simple 4 purchases of this easy to swallow CE deal will make up the cost of the less casual $9.95 deal.
In this time of seemingly high Energy prices, people may be more likely to buy, but with prices rising, it may be safe to say they aren't yet willing to drop a 10 dollar bill for their energy. With a more approachable $2.45 deal, player may be willing to buy more energy.
E: While switching to Paypal or taking advantage of other methods may be viable, this removal of the 2.45 energy deal purchase able with a credit card does make things less convenient.
I still see that offer. What method of payment do you use and where do you live?
If you dont believe me, it's actually $2.45, and thanks to the 10% bonus wich expires today, gives 826 energy. Using paypal.