nothing is perfect in this world, but if it happens, it will take a very long time, when they tried to hack her, the bitcoin users also fix all the weaknesses that exist within bitcoin, all of this has always kept a continuous
well bitcoin seems to be perfect currency right now, but it has to be updated from time to time, because the thing that is not evolving with time is going to be replaced by something else, like cash is going to be replaced by bitcoins
Well if you see how bitcoin crashed 2 times in 1 month you can see it's not very strong. Then we have the blocksize debate where parties are not seeming to agree what needs to happen