We don't know the current peak capability of quantum computing as it is still in its early stages but one thing is sure that it will be a problem for bitcoin because as what is on the paper says about quantum computing, it will be far faster than any computer in the market and in any laboratories.
You might be right but I am a firm believer that it can affect bitcoin big time, we can't see the peak but we can still imagine what it will do, remember the first computer which is the size of one room, they were much slower back then but we came to the stage that almost every household has a computer which means that quantum computer capabilities might do what we didn't expect it to do at unexpected speed.
We also have to stop telling people that quantum computing will be able to hack the private key of everyone, yes it has faster calculations but that doesn't mean that it will crack the key in a matter of days, if right now the current brute force duration is the heat death of the universe, maybe with quantum computing, the time it takes will be cut in half but that is still a whole lot of millennia.
I find it funny that people are talking about quantum computers breaking the security of blockchain so I wouldn't want them people to stop telling about it because I want them to see what they are going to say when you ask them why. Is that really the time it takes to crack the private key with brute force? That is a really long time, I might do some quick search about the duration but I am sure that it will not be as long as the death of universe.