Yeah, of course airplane mode makes my phone last longer, but what's the point of a phone in airplane mode?

It lasts longer if I turn it off too.

At this point I just accept that I have to bring a battery brick with me everywhere, it's fine.

I mean, if it's out of charge anyway, it'd seem more useful to be able to turn it on/off and use it sporadically or at the end to get back

A battery pack does make it pointless though