I don't know how much of a difference it will make.

It's easy to host files. Even if the malware "author" is clueless and just buying a customizable malware, either they'll figure out how to host files or file hosting will be provided along with the service they're buying.

It may not stop Discord from being the file host either. Malware distributing bot accounts could keep copying a new link to the file, or could upload a new version of the file on demand.

Discord can't expire webhooks the same way so webhooks will continue to be used for exfiltration. Pointing out that it's used for exfiltration as if it were related seems like bad reporting. It's a difficult problem because if they did break webhooks it'd only make things more difficult for legitimate users. These malware packages usually hijack the user's Discord installation and could send out the information as the user without using webhooks.