I wouldn't assume an eRoad bike is quicker, my own experience of my 250watt Fazua hybrid mirrors what this reviewer found, am slower on my eBike than my road bike.
But that doesn't mean the eBike is useless, I did a 7 mile trip the other day I got a half decent work out - averaging 110watts versus 160watts I normally achieve on my road bike.
However to achieve the same speed without electrical assistance I would have needed to put out 200watts+ due to the area difference between a road bike and hybrid bike.
Been able to achieve half decent speed with less power is quite useful, for example later today I'll be cycling to a friends house on the eBike rather than road bike, as I would like to get there not covered in sweat, and negotiating Nottingham city centre is much easier on a hybrid bike than my road bike with clipping pedals - especially as I've not ridden on those road before so will be navigating and cycling as well.
With a 400watts Bosch motor you will get even more assistance than what I get on my Fazua powered biked.