It makes the bike a little lighter, a little easier to work on (for those of us who know how to use a DVOM), and allows for another level of programming to make the bike faster and easier to ride.
One flaw of most bikes is cost/space restraints mean they have butterfly-type throttles, which have a very steep airflow curve. That's why 1/4 throttle is almost full throttle on bikes (and cars..)
The throttle by wire would allow you to program around this, giving the rider better control over the bike's acceleration, as long as he can get used to the system over normal bikes.
Throttle by wire also allows for zero-extra-weight cruise control and takes us one step closer to having CAN on our bikes.
Even drag racers will appreciate having less stuff to route around their big-ass turbos, and it can even allow you to have an integrated NOS system with less wiring.
As far as cost, it's actually negligable. Parts go like this:
+Sensor on throttle grip
- Cable assembly
+Motor to move throttle plates
-Idle air control (if equipped)
The individual parts may cost more, but it allows a lot more uniformity in the manufacturing process, which saves them money, which saves you money...
The cost of bikes is almost entirely market driven anyway.
It also makes it easier to control idle, and simplifies traction control greatly. You can also TUNE ENGINE BRAKING by allowing the rider to slam off the grip and measure how much air you want to be continually let into the cylinders, something MV Augusta (I think?) already does (with a different system).
