I see being able to "update", or in effect "reopen", an existing support ticket via email (with the Ticket Number in the Subject line, of course) as being more convenient that going back to the panel to "re-open" the ticket; but that is just my opinion - YMMV.
I mean, how much easier can it be to just "reply" to the email you received from support to "continue" the ticket. WHile generally speaking, DH suppor has resolved my issues with a single response, I have had several situations where we exchanged several email, over several days, all on the same "ticket" - just responding to each other's emails. At any rate, it has worked well for me. 
--rlparker