Warlock's spell slots

I don't get the spell slot system for D&D 5e's Warlocks warlock spell slot Warlocks don't get the same leveled spell slots like other full spellcasters Instead of selecting a slot to expend for appropriate spell warlock spell slot table Warlocks do not cast spells through the Spellcasting feature, but through their unique Pact Magic feature Spell slots granted by Pact Magic are

warlocks book slot Hunger of Hadar​ giving full control of the battlefield Warlock's spell slots also restore on short rest, but this is not a major point in my