Here's the bottom line, and I can see Fraggle's and the game's side of this.
If that rule wasn't in place, the company would lose money on an extreme level.
Most people wouldn't pay money for credits, because they could just work an account up enough have 50 clintz, sell cards to themselves, and trade off all their dupes for the free cards they got when they created their second account by selling a card to their 2nd account, and rinse repeat until they had most of the collection.
The buying credits at least prevents this on some scale since the company has to benefit at least marginally for this to occur, and if you're gonna go through all that trouble and end up spending money anyway you may as well just do it for the one account.
This benefits you too because it keeps the game around and alive for you to enjoy. Servers, domain names, etc are not cheap, and as such they have to raise capital just to cover that, not to mention paying people like Fraggle here, the programmers who work quite hard to make the game what it is, etc.
And really compared to other CCGs this one is relatively inexpensive. 20 bucks american to get 400 credits which gets you 8 of the 8 card packs
, is a really inexpensive way to get a starting collection. You can't get 8 packs
of any other CCG and have a playable deck for I can think of for 20 bucks.
Sure you can buy starter decks for 20 bucks and they're "playable" but they tend to not be that great.
So really as far as CCGs go this is one of the best deals out there.