Hehe, a very nice little video, I had no idea that was around XD

When Zho is a medic and spotting the armor taking a silo, that is extremely important as, if he can't damage it, then his entire team would know that:

Firstly, enemies are still there and the neutral silo is not about to be captured by a friendly again (Zho).
Secondly, that it is armor doing the capturing and a friendly tank, walker, gunship or engie may head your way.
Third, where it is - so that any of the above have more luck taking it by surprise and hitting it accurately.

Basically...it does a lot more things than just shooting or running away would accomplish (add VOIP spots though by all means).