Because as far as I can see, it is integrated with the default gas tank, so you don't need to stop to refill the built-in tank manually or worry about managing the two tanks separately.

So this extension functionally works as if your single tank just got larger. Might not be something that everyone cares about, but the value proposition over a jerrycan is clear.

Sure, I got that aspect. For me the argument going the other way is:

1. Generally you don't need the excess range, and this thing seems like a relatively permanent modification, so you're dealing with the excess weight/bulk all the time, and getting the added benefit only when you actually need to do the long haul.

2. This Ducati thing is only 8 liters, and adds 40% to your range.

So a jerrycan would (more) easily be added/removed as needed, and holds 20 liters, doubling your range. You could even add two, to triple your range.

Also, there's the fact that a jerrycan costs about $40, while the Ducati tank costs... $1900!? Yikes -- yeah, I'm sticking with the jerrycan :-)

Well the weight is distributed lower and it would survive being dropped offroad and so on...

But I get it -- I've ridden with Gatorade bottles full of spare gasoline too (yes it'll eventually eat through the plastic, but not fast enough to matter in my experience.)

> I've ridden with Gatorade bottles full of gasoline

Samesies! I once ran out of gas on a GS-550, walked to a Circle-K, bought and drank a quart of milk (I'm not much for gatorade) then bought enough gas to lightly rinse out the paper carton and then fill it to take back to my bike. This was a long time ago, please don't judge me :-)