It looks there is no difference in charging speed with and without Steady Charging enabled. Charging from 20% up to 80%, in both cases takes ~30 minutes. All system updates are installed. That is an important functionality for increasing the battery lifespan.
I use old chargers from previous phones 5V 1.5A(7.5W), 5V 0.85A(4.5W) and i think, this prolong battery lifespan ... This chargers are good for night charging(LOT of tíme) or i use slow chargers when im at work ... I use original fast charger only when im hurry... With 7.5W charger i need from 0 to 100% 3 hours. With 4.5W 5 hours .. this is really slow charging and saves battery... Also good option is 5V2A (10W)
I noticed this behaviour and agree that it should be fixed, because even though re-using an old charger is good for the environment, we should be able to use the included charger with all advertised features.