I will start worrying (and educating myself) about quantum computers when they start factoring very large numbers. Until then...same category as interdimensional aliens using advanced technology to hijack the blockchain.
It has already been done. So start worrying.
I believe that the NSA has already developed/purchased to help them handle all their data they get from their spying programs. I believe it was also very expensive (in the billions of dollars).
Actually a Canadian Company developed them at $10 million per pop. They were heavily funded by Jeff Bezos of Amazon.com and the CIA. Lockheed Martin bought the first one and a university used one to solve complex equations that were not solvable until this thing came out.
http://www.dwavesys.com/The majority of the scientific community laughs on this project for almost 10 years now.
It's not quantum. Both in theory and practice.
Actually in practice things are even worse with generic computers outperforming d-wave in many cases.
Get over it. There is no quantum computing. There is research but atm with
zero results.