The world is also full of thieves and robbers. And don't forget about government as well which may also want to set their greedy eyes on your gold that you have providently buried in the backyard of your home...
Maybe, your neighbor is spying on you this very moment
As you mentioned there are a lot of problems and inconvenience and insecurity while storing our money in gold, as gold has some volume while there is no any issue with bitcoin like that, bitcoin is a virtual currency and these are locked in your wallet and no one have access to your bitcoins but only your mind have access to them.