This is not a practice management or time recording system. It will not run your billing, your matter files, your document management or your conflicts process, and it should not try to. Keep deliverables and formal advice in the systems built for them, and use the CRM for the enquiry, the proposal and the relationship history.
WhatsApp itself has constraints worth knowing. Promotional or re-engagement messages need approved templates and prior opt-in, free-form replies work inside the service window that opens when the client writes, and Meta charges for conversations. Professional firms rarely need bulk messaging anyway, so this matters less here than in retail, but do not build a plan around broadcasting to your client base.
Finally, culture beats configuration. Partners who keep a private list will undermine any pipeline view. The firms that get value are the ones where the weekly partner meeting uses the pipeline on screen as the single agenda, which quietly forces the records to stay current.