>>96278942
You don't NEED them (Skaven you kinda do, but you could just effectively use a piece of paper in the same size and call it a day) Endless spells goes the same way, your mileage may vary depending on which spells. They're just extra stuff if you have lots of casting available, and fun models to paint. I don't think any faction NEEDS endless spells, but sometimes they're pretty fucking cool.