I think it says the opposite actually, that using encrypted DNS alone is only useful for circumventing content restrictions implemented by DNS blocking.
This is because even if you use encrypted DNS, your ISP still sees the IP of the website you are visiting (as you noted), and they still see the domain of the website you are visiting even with HTTPS because of SNI (encrypted SNI fixes this, but it is not widely used yet, and it still doesn’t fix the IP issue of course).
Therefore, the disclaimer is saying that if you want privacy from your ISP, you must use a VPN (or Tor, etc.), you cannot use encrypted DNS alone.