People can appreciate not getting the deal you wan and walking away, but when you go into a meeting with a signing ceremony on the scheduled, you give the impression you have everything under control and ready to roll. Walking away in this manner give the optics of not being prepared. Would not be surprised if Trump got rolled by Bolton, and the bad optics was Bolton's way of weakening Trump. If so, he will pay in time so long as the clock doesn't run out, which is exactly the tactic the DS has been using on Trump so far.