What was the reason to not include them as cards is just my guessing but enough attendible I think. It seems the MB standard production for cards was a deck of 64 cards. 64 was the cards in the European Game-System and 64 was also the number of cards coming with the Wizards of Morcar pack. It seems they added lot of extra Men-at-Arms cards to fill the deck and reach the desidered number of 64. This would also explain why there was only five Helbardier cards against the six featured for each of the other Men-at-Arms type. Space Crusade (aka Star Quest) was also featuring a deck of 64 cards. It is possible They didn't have enough cards for Against the Ogre Horde pack (only 3 spells and 4 monster cards) to be worth the production of a new deck. This would also explain why they put the four Ogre Monster cards on the rear of the questbook, to be cut, instead of using standard cards.
So, going back to the Chaos Spells, I recently converted the tokens into cards to match the style of my other custom made European Chaos Spells. I re-wrote a bit the text for each spell as the original tokens text was only partially written and you needed to read the full description inside the questbook to properly understand how each of these spells was intended to work (check the picture below).