Safe in the sense that gold and silver have been around for thousands of years and we know that it holds value well in all circumstances.
While bitcoin has been there for a few years and we are at a point in the history of humanity where nobody can possibly know where we are going at social/economical/technological/political/environmental level which creates much more uncertainty on bitcoin than on gold and forces to admit that bitcoin could be worth zero in a minority of scenarios while gold will hold its value with more certainty.