I think he meant it acts more like glass or dim glowstone. In that case (athough I have no confirmation of this), it would be possible to rig a trap where a player walks over a redstone ore, which then stops blocking a redstone signal passing underneath it, triggering some TNT or something.Transparent? I knew it glowed; I did not know mobs could see through it.
There aren't many blocks that mobs can see through at all- with the exception of spiders and mobs that are already aggroed at you, almost any block (probably including glass and torches) will block mobs' line of sight. Spiders can see you through anything, and aggressive mobs that have already spotted you will chase you despite almost anything in the way.