High base damage makes them still just as effective at dishing out damage without building much damage.
The other day me and my friend were playing bot lane I was Soraka and he was Quinn, we were matched against Rengar and maybe Vayne. Anyway, we had a rough start and at level 3 Rengar instakilled me from full health to 0. I died a couple of times in lane, but we ended up easily winning because it turns out that having a support is > > > having an extra bruiser instead.