If you want to have mana all the time, you can set it that way, if you just want the passive generation to be a small supplement to your resources, you can do that as well.
This mods aims to try and make a 'full' magic user build more viable, by allowing mana to not just regenerate from resting, but passively even while not sleeping. In a similar vein to how passive mana regen works in Oblivion and Skyrim. The main reason being that using magic can be very expensive in terms of dealing damage, and the player mana pool is only so large that most encounters will leave them without mana to continue fighting, so they have to switch back to being a melee fighter essentially most of the time.
