It's enough to fully eliminate the possibility that someone steals your account by finding your password in a leaked database for another service, which is how the majority of "hacks" happen. Like, pretend for a second your email is "[email protected]" and your Neopets password was "Yeahdogzrule1988", if that Neopets info leaks (and it has before) the fact that that email and password were used together before is a publicly available fact, why would you re-use a password that other people know (or can later learn) is one you use?

There's no guarantee that's what happens here, but then again the people getting hacked are not instantly saying "My Genshin account had a unique password", which is something you'd expect them to say as a pretty important factor. There are other possibilities, but this is the one that makes the most sense.