It's in the translator's interest to keep the buffer for themselves if they have a fall out with the website - ruins the site's reputation.
But pretty sure Webnovel would have had them sign a contract that protects that from happening.
So maybe they just don't consider this a good enough reason to use the buffer? (Even though it's THE reason)
Seriously, I've never seen a website be handled so poorly, and I (as do many of us) visit many third party translator websites, so what the hell?