Hi Shuey,
I see your point, and raise it with a wtf?
I bought the BMW charger at my RIS as advised. It's on it all the time. But the manual says if you leave your bike more than 4 weeks, you should consider putting it on charge.
I've been a biker all my life. I've bought the BMW lithium charger and can connect it easily enough (with the terminals I bodged myself) because I have power to my garage, but I'm used to being a daily biker and not needing to rely on a charger. It was a source of miserable reflection for me when the kids arrived, that I realised that I was no longer riding often enough to never have to think about how long a battery charge would last.
I had to think long and hard about whether to buy another sportsbike which would be, essentially, a luxury toy. I decided to pay extra for the weight-saving of a lithium battery, and then got sucked into the Sport package (I don't need forged wheels any more than anyone else, but I like the idea). I hoped to get a lighter, better, modern battery (a ?200 option without the wheels).
I should not expect a battery to last less than a week on a ?20k+ road bike, when my CBR still fires up after 3 months neglect.
What if I want actually to travel somewhere further than a tank-full on it and stay still for a week? In real life, I might not, but that's not the point.