Why is Righteous Glory a good rush item after Cinderhulk?

Is running towards the enemy quickly really that useful early game? +500 health +70 armor Passive UNIQUE PASSIVE – COLD STEEL: When hit by basic attacks, reduces the attacker's attack speed by 15% for 1 second. Active UNIQUE ACTIVE: Slows the movement speed of nearby enemy units by 35% for 2 (+ 0.5% armor) (+ 0.5% magic resistance) seconds. 60 second cooldown (500 Range). 2850 Gold

+600 health +300 mana +100% health regeneration Passive UNIQUE PASSIVE – VALOR'S REWARD: On leveling up, restores 150 health and 200 mana over 8 seconds. Active UNIQUE ACTIVE: Grants +60% Movement Speed to you and nearby allies when moving towards enemies for 3 seconds. When this speed boost ends, it emits a shockwave, slowing nearby enemy champions by 80% for one second. 60 second cooldown. 2500 Gold

For 350 gold you gain armour and attack speed reduction and lose 300 Mana, 100 health and ( Active UNIQUE ACTIVE: Grants +60% Movement Speed to you and nearby allies when moving towards enemies for 3 seconds. When this speed boost ends, it emits a shockwave, slowing nearby enemy champions by 80% for one second.

For champions like my main I don't find the need to run up to the enemy necessary and I tend to rush because the CDR is crucial for the early game ganks and teamfights. I know the META is health but I find a weak first item after cinderhulk.