This is a great discussion. I think the real value of one agent across all channels is not just less maintenance, it is consistency. A customer should not have to repeat themselves just because they switched from chat to email. If the context follows them, that is a huge win. But I agree with what others have said. Voice is very different from WhatsApp or email. The shared knowledge helps, but each channel still needs its own behavior and tone. The setup has to be flexible enough to handle that without becoming a mess to manage.