On the Viper Mk III that I have the battery is in an accessible compartment and is held in place by a Velcro strip, so easily changed out.
I cannot see the sense, or the design parameters, of having the battery in an inaccessible or closed compartment.
When I was doing a lot of Carp fishing then the boat was very useful to get to places where casting was pretty much impossible, and yet still a safe fishing situation.
Also, the ability to be wholly accurate in positioning the baited hook together with a quantity of feed is just not manageable with a catapult alone, and I am very accurate with the 'pult.
I am not saying that the boat was used on every trip, in fact probably only one in five or six, but when it was employed it gave results that were not possible with conventional means.