In the UK the Lumix is approximately the same price, £10 difference.
If I lived in the desert I'd definitely be going for weather sealing, that fine sand gets into the finest places, just look at what the camels there had to do
It was weather sealing on lower end Pentax cameras/lenses back in 2012 which swayed me over the other DSLR brands which completely lacked WR. Here in Ireland it's more rain, pollen and sea spray from storm photo/videography I need it for. Even tiny insects can make their way in.