Because email is one-way. Having raised a ticket, the only way to find out what is happening is to email again — which creates work for both sides and often a duplicate ticket.
The portal is the customer's own view of their support: open tickets, history, entitlement and the knowledge base.
Contacts sign in and see their organisation's tickets, current states and what is waiting on them. Raising a ticket here captures the fields support actually needs, rather than a paragraph of prose.
A customer wondering about a ticket opens the portal, sees it is with engineering with a target date, and does not send the chasing email.
It never shows internal notes, other customers, or your costs. Internal notes are a separate field rather than a permission, so they cannot be exposed by misconfiguration.
Their tickets, their entitlement, relevant knowledge base articles, and — where you expose it — their project delivery in Loop.
Yes, within their organisation, if you allow it — off by default.
Yes, within a window you set.
Yes, for customers who want it.
Fourteen days, every module, no card. Or half an hour with someone who will run it on your own records and tell you where it does not help.