Dark Souls 1s spell limit is better than the mana bar of later entries.

It balanced the pros of having spells that are always reliably there and don’t fight for space with the other spells with the restrictions that you can’t go nuts and overly rely on a spell too much.

Why use a healing spell that needs to be replenished with a blue flask in later entries when you could just allocate that flask as red instead? But in DS1 that healing spell is just a bonus you have in your back pocket regardless of how many other spells you’ve cast so far.