You are right, but isnt winning the real objective of Battle? Or is it so trivial compared to having a good k/d on the website?
For most player it is i guess. At least "in the moment" of playing. When you're running around on a battleserver, you wanna kill as many opponents as possible, and, if you're not able to steamroll the server with your clan, you're just trying to survive and maybe get a few kills. I'm talking about how it feels - not about what its meant to be. I doubt theres many solo players on battle thinking "i so wanna win this round" - it's more like "damn archus. Ima hide and fight the unaware when i'm last... maybe i get valor". Battle kinda forces you to think in survival ways, cus it punishes your death with long waiting time (and bad K:D - which is important to some poor creatures too).
Siege is way more casual and arcade even... you're much more careless about your own life, cus you've got plenty and can focus more on objectives.