Confusion with card's category

[Bruele]

What s the sense of divide the spells in "spells", "organic", "bomb", "tactic", "spells without category"?

 

[4RM3D]

Organic cards can be tutored my Monsters, Tactics by NG and it's important for Ardal. Bombs is just for lore, right now, but later on they could also get some special interaction.

 

[Bruele]

And the spells that don t have "spells" in their category?