card series

ok.. too drunk and too lazy to check if people have discussed this here (yes they have.. but not on the aspect i want)...
so here it is:
1 -Everybody knows that trading cards nowadays are "series 1"... which implies the possibility of series 2..3 and so on...
2 -changing briefly the topic, crafting badges in this last sale was way more profitable than doing so on regular basis.. since we would receive a bonus card (0.20 dollar gurai) ....

so.... what do you guys think? economically speaking crafting cards is not usefull (has that 'nice' feeling but that's it..). Should i save my cards for next sale... (hoping a similar event..).. Should i save them in hope a series 2 will be launched and, therefore, i'll be rich.... should I sell them all? or just forget aboutj profit?