I accidentally bought a phone (LG G3) with a removable battery.
Now I realise that there are benefits to having a battery with it's own (thin) case, that sits in a dedicated space, not squashed in, glued, bent or otherwise mishandled. Apart from being able to change it in 10 seconds. Long live my new (old) G3! (The quad HD display is magnificent too.)
It has a new LG battery, BTW.