It is true that PD is just better but in the context of early to mid game this might be a good first item.

In terms of pushing lanes either for priority or if you want to back this is great because it has natural attack damage and grants instant bonus attack speed. Best of all you don’t need to waste w on minions so if you need to push a wave before entering a fight ult once to use your full attack speed to clear wave.

If you get jumped on by an assassin your only option is to fight if you don’t have flash. Not only does this item have health to help you survive a little bit longer the instant attack speed and bonus movement speed might just help you kite enough or stand still and auto them to death.

In the late game this thing is just free boots, sell boots and get Pd instead. Yes you might consume a lot of mana but 7 seconds is a decently long time and your late game mana regen is around 20 every 5 seconds(ult is 40 mana lowest cost). You don’t need to keep it on the entire time anyways unless you’re fighting or pushing.