Good questions.
First, the WC guard sits about sternum level, both hands lined up with center. In theory, you move fast enough from there to stop incoming strikes along the centerline to close to trapping/chi sau range and beat them at the short game. This is problematic for many reasons.
1) your hands are only covering the center of your upper body. From here any strike hits you if you don't move.
2) from 1. This hand positioning not only requires that you be significantly faster than your opponent, you also need to be able to read his strikes before he throws them. Unless you are a superhuman, this isn't realistic
3) even if you are somehow that fast, anything coming on a curved line requires you to shift your body position/centerline to stop, which requires you to be even more superhuman, especially if you get two in a row from opposite sides.
4) the strikes you can throw from there are extremely limited, and lack the sort of power you can get elsewise.
5) the stance is quite rooted for a system that requires slick and quick entries to work.
Now as for 'blocking', yes and no. I keep my hands high so I am covered, and 'block' by either using a short pak sau/parry or by rolling my shoulders up into a 'hair comb ' cover. This combined with foot movement, head movement, slips and weaves. The best 'block' imo is making him miss.
If you mean, do I throw my arm out to meet his arm...no...never.