The bad points I see are these:
Many people are sending these off really early by rote when asked to by their party organizers. So they reflect nothing of the campaign itself.
Seems wrong to skip the debate.
The other big problem is that they are notoriously hard to count.
One reason for that is that you don’t know until the actual day if someone will void his ballot by voting.
And all are hand counted, so they trail in several days later.