It depends. Quite often (this is how you can tell I live in Germany) mobile data switches to "you're at the EDGE of the network range" mode¹ and transferring a few KB means keeping the screen on and radio active for a couple of minutes. If the page is now 45KB instead of 95KB, that's a significant reduction in battery drain!

Under normal circumstances you're probably very right

¹ Now I wonder if the makers foresaw how their protocol name might sound to us now