The Explorer Pack costs $2.95 as of now, which is only slightly more expensive than the 750 CE package ($2.45). Yet, it gives
1000 CE
1 Silver Key, or 750 CE
1 7-day Heat Amp, or 1600 CE
1 14-day Elevator Pass, or $3 if it could be bought independently (worth another Explorer Pack all by itself)
In total, you get 1000 CE and the benefits of another 5700, and I didn't even count in the Stranger Hat.
It's still kind of weird. Even if it was for Christmas.
Yeah, but Silver keys aren't worth 750CE to most people and heat amplifiers are worth next to nothing. Still the 1000CE and the elevator pass make this a very good deal, just not as good as OOO hypes it up to be.
They have been acquired by Sega, meaning they're financially more secure. It might be that financial stability is the very reason they can afford to give us nicer deals (on festive occasions).
Also consider that elevator costs are something we're used to, it still doesn't cost them a bit. Eliminating the elevator cost is a relatively small hit on their profits (we just quit playing that day), but for us it's a big deal. We're still buying a currency they can make infinitely without limit.
There is also the sneaky psychological trick that if you convince a customer to pay for energy once (no matter how small) it'll be significantly easier to purchase more in the future. This has a snowballing effect, you might buy a pack today for 1000 energy and 2 weeks of free diving, but the ease of making your last 5* item (with the 1000 energy) will stick with you the next week. Why not buy 3500 energy, since you have 3 more 5* items to make for your full set?
I think if they were desperate they'd start selling very nice UV'd items for real money, selling out as it were.
Its kind of SUPER UBER MEGA promo, they say that it will cost ~15$ after X-mass and new year. I think OOO wants to have some merry X-mass and get $$$ under their Green Tree.