According to external sources, Google has already designed a Quantum Computer that's much more powerful than its competitors (like IBM and other mainstream companies working on this). Nonetheless, do you think that Google's Quantum Computer will be able to destroy Bitcoin in the future? Or will the pioneer cryptocurrency adapt itself against this new trend? 
There is this pervading fear among many Bitcoin enthusiasts/hodlers/lovers about the threat of supercomputers (quantum) that can possibly decipher the blockchain and destroy Bitcoin at a glance. However, up to now, no one can give us a proof that what Google developed so far can really do this. Maybe this is just akin to spreading FUD and partly marketing the technology that Google has at hand. I am sure that Google stands to make billions with this development and they are in fact withholding information so people will talk about this themselves...getting free promotions along the way. Genius! I am sharing this good article on Google's quantum technology that can possibly clarify this thing and erase our fears.
I guess there is nothing to worry about at least not at the moment because I believe Google won't allocate its resources just to destroy a cryptocurrency and for what?
Also, if ever time will come it would be possible to crack Bitcoin with quantum computers, I guess developers, together with the community would by far already have applied technologies to Bitcoin to make is quantum resistant and since there has been crytpo projects that supposedly claimed to be quantum resistant, maybe the developers could use it or improve upon those technologies to make it applicable to Bitcoin.