All cards should be purchasable via credits in the standard way.
This belief is really the crux of the discussion in this thread and so many others. Admittedly, special event cards are different than how VGHD/iStripper has worked in the past, but it's not inherently "wrong" or even disrespectful to loyal customers. It's a commonly used model in the collectables business.
For example, I know people who have literally crates full of Magic the Gathering cards representing thousands of dollars of investment over years of playing, but that doesn't mean they get to buy the rare cards in each new release for the price of a single booster pack. Some of them do gamble and spend crazy amounts of money on sealed packs in hopes of getting the rare cards they want, but it's usually frustrating and futile. Most players eventually accept the fact that there are some cards they really want but might never get and they learn to enjoy playing the game with the cards they have. Again, that's a change in the iStripper model, but if Totem chooses to keep producing special event cards, users will probably change their expectations accordingly.
Regarding gambling, some people actually do enjoy it whether they win or lose. For everyone else, I'd recommend that they abstain from the slot machine and scratch card promotions and just buy themselves a card or two for full price at the end of the week as a reward for resisting tempation. Most will find themselves far happier for it.
😊 
