Speed and practicality. My base for each character is a very dense open shack with only what I actually need to craft and sleep. Only exception is that I sometimes put fences around my garden when mobs start having a tendency to wander in. I found trenching boring, tedious, and of questionable benefit. During raids (if I am home) I walk a short distance outside my home and deal with it, no damage to my base. Only time I ever consider trenching is for the wolf raid and only if there are no rocks anywhere close to my base. Even the seeker raid is manageable without trenches, well timed controlled mini sprints work wonders.