Depends how your layout is run. On my layout I use Air for Points. It is quite possible to have points Operated from 2 Locations with a Shuttle Valve, this means you can have either a Local Panel or the Points can be operated from a Central one. The best of both worlds.I know that logically it must be possible to wire up a battery to a point motor but, unless the battery is left in situ and hooked up to some kind of permanent charging arrangement, wouldn't every running session need to be preceded by a process of ensuring every point/signal motor has adequate battery power and. if not, installing fully charged batteries? This sounds like much more of a faff than simply turing on the power to the layout.
Cheers
Of course you could install Mechanical Signal Boxes for Point Control, but these would cetainly need to be more locally based if you have more than one Station. This is how I have set up my Air based system with Local Pannels at each of my 8 Stations.
Or you could have DCC Operated Points and Signals on a Bus with a lower powered DCC System and run via a Computer, effectively like a Modern Power Signal Box.
Plenty of options without needing Battery Power for the Points and Signals.
JonD