CAI-302 and XCSoar

I've never been able to figure out what the benefit would be from
knowing the outside air temperature. I've bought different computers
over the years that come with OAT sensors but I never bother to
install them because I can't see how they can make my glider go any
faster. I actually have built in sensors to tell me wether I'm cold
or not and there ain't much to do about that anyway. When I'm cold it
has as much to do with lack of sunshine as it does with air
temperature. So, what's the deal with OAT? Why does anyone care?
Why are these sensors being pushed on me?