Technically Magic: The Gathering also doesn't require booster packs to be played. The starters are enough. But I think we all know how the reality looks like.
Doesn't feel like a really good comparison, at least not to me.
If playing Magic competitively, you want more cards to be able to build better decks. That doesn't really map over to a situation like this, where you don't have the same sort of direct competition nor do you get any huge power boost from buying the boosters.
If not playing Magic competitively, one is probably just playing for fun, and one might get more cards to try out different decks or keep the game from getting stale. But the cards are one element in an RPG - the bulk of the entertainment comes more from the adventure itself, and that will constantly be changing from one session to the next.
I'm sure some people will go hog-wild and buy tons of these boosters. Just like some people have closets filled with D&D minis or jars filled with Dice. Some people have one battle-mat for the game, others have hundreds of dungeon tiles, and others don't bother with mapping the game out at all.
Buying more cards is a core part of magic. But the boosters here are an accessories, just like D&D minis. Some will pick up tons of them, some will snag a few packs, and many won't bother with them at all.
Thanks for the explanation. However card rarity implies that some cards will just be better than others. Maybe I'm completely wrong about that, but why else would they be rare?
Is there some mechanic that prevents the player from stacking his deck with rares other than they have to be different, and to avoid ridicule from fellow players and the GM? I know of such players that are resist 20 to that kind of ridicule.
I'll try and take a closer look when I have a chance (though I only have the one booster to make comparisons from.) The rares didn't seem exceptionally more powerful than normal cards - maybe slightly so, doing an extra die of damage or whatever, but the rarity seemed more about them being less common or more exciting mutations than anything else. But I'm going on memory and an extremely small sample size here, so I might be wrong about that.
From what I recall about the player deck, the limitations mainly are that:
-I don't think they can have more than 2 copies of any given card;
-They have a 50/50 chance, I think, of having to draw from the DM deck anyway;
-Pretty much all mutations are beneficial, so the differences between getting some cool mutation you prefer for the character, and some other random mutation from the DM deck, is pretty slim.
Again, not having seen all the mutations, I can't say this for sure. But I get the sense that a player with their own personally chosen mutation deck will have less of a boost in power than... well, any D&D game in which one character is min/maxed and the others aren't. The characters in Gamma World just seem on a tightly balanced enough scale, and the mutations are unreliable enough, that I can't forsee any real abuse of the system.