If laptop batteries can't grow, I assume there'll be a little extra pressure towards saving power, as people try to progress somewhere.

ARM laptops are said to be much more efficient than Intel. Just two cents' worth of hearsay.

Size is fine, what I despise is that most laptops I've tried to keep alive over the past 10+ years, simply don't work without, at least, a minimally functioning battery installed. I should be able to take the battery out and use the laptop plugged in without fear of the dying battery exploding.