no it's not. And yes you SHOULD build this even as an adc and no it wont hurt your DAMAGE because you will actually be alive to deal it. Alot of damage is useless if you can't deal it.
When Rengar is 29 and 0 and the adc still wants to leave tower. https://i.gyazo.com/255b01beda12719916fd5174ca13ad8f.jpg