Where's the benefit if....

[Manaz]

I think you answered your own question there buddy. Chip = more power = faster car. If you don't need faster car, don't get a chip. Simple

It's far from that simple.

In order to protect cars against lowest-common-denominator owners (who never service, run ****e fuel, don't check tyre pressures or fluid levels, etc), most cars run quite rich when stock. This wastes fuel, as not all of the fuel injected into the combustion chambers burns properly, and hence is wasted.

Chipping a car (or flashing its ECU, whatever you decide to call it) adjusts a few things - changes fueling maps, increases timing, increases boost if you have a turbo, and these serve to do two things primarily:

1. Increase efficiency.
2. Increase torque (and thus power - power being a function of torque).

Note that the two are quite intertwined - increased torque production comes at least partially as a result of increased efficiency.

Now, if you don't use the increased top end power (and let's be honest, it's rare that you use the extra few top end kilowatts you might get), you're almost certainly using the increased torque across the rev range - with more torque, the engine doesn't have to work as hard (you get increased driveability), and along with the fact that it's running more efficiently due to better fueling maps, you end up using less fuel.

So even if you're not chasing outright power, chipping/flashing a car can result in a car that's easier to drive and that uses less fuel. I'd hardly call those two benefits poor second place options behind outright power gain, particularly given that they're encountered and taken advantage of far more often than top end power ever will be.