I agree that having more features for a cost in term of battery life is a good trade-off. Still, the battery life argument is a good one when considering buying a new phone.
Between different brands and models, you see a huge difference in term of battery life (think Motorola Android phones VS Apple iPhone 5).
I see as an advantage not having to charge my phone every night, I like knowing that if I forget my charger when travelling, my phone won't be dead after a single day. This is just my personal experience, some people call a lot, some people go on the Internet a lot through 3G (and most phones out there won't last the entire day doing that), or simply the fact of knowing that after a few months of usage, my battery life won't be down to a few hours (yes, battery life goes worse with usage).