Mods like GB WhatsApp promise extra features: deeper customization, hiding read receipts or online status, and running multiple accounts. None of it is sanctioned by Meta, and none of it goes through official app store review.
The risks are stated by WhatsApp itself. An account that uses an unofficial app can be banned temporarily or permanently, or restricted, including in its ability to link devices. And because WhatsApp cannot validate the security of these apps, they might carry malware that steals data, with no guarantee that messages, location or shared files stay private.
For anyone, and especially for a business, the safe path is the official WhatsApp or WhatsApp Business App, and the API for automation. A banned number takes its chats, its contacts, and its customers' trust down with it.
One name causes confusion: "WhatsApp Plus" is now also an official, optional subscription offered by Meta inside WhatsApp Messenger. It is not a separate app and requires no download, and it is unrelated to the unofficial app of the same name.