Central banks can only create high powered money.
How high powered money gets intermediated into actual economic activity is probably one of the largest unknown factors in central banking/monetary policy. This would, in theory, remove that discussion.
That being said, if you are familiar with the history of monetary policy across countries, there is already quite a significant spectrum of central banks adopting new approaches to this problem. And it is not particularly evident that removing banks from the equation improves outcomes (although this is one of those lessons that falls in the blind spot of certain popular ideologies today).
Simply: when you talk about disintermediation of banks, you get into the discussion of whether central banks are able to make lending decisions better than banks. When this works, as in Japan pre-1991, it works very well...Japan post-1991 demonstrates that it doesn't always work well.
Also, this would change the politics of monetary policy. Most monetary systems that disintermediate banks are usually one-party states with extremely high levels of centralization of economic authority (you also tend to see heavily monopolized banking sectors, the US is the polar opposite of this, although this may not apply in this case). I am 95% sure that if you attempt to do this in a democracy, you will Zimbabwe your currency quickly and trigger a move away from democracy (unf, this also falls into a blindspot of lots of people today...economics PHds don't learn this stuff). It is very hard to have stable politics when the winner of an election will gain the power to make their family/their associates/all political allies permanently wealthy.
EDIT: because I cannot reply, if you are asking how this fails to change anything...read a monetary policy textbook. There is a deep lack of understanding about basic elements of the financial system here (as ever). This isn't a facetious comment...srs, read a book.