Whats the deal with Lightning Strike Templar?

Been playing my Smite/Spark mace and shield Templar with great success all the way through Act 1. Saw a lot of posts and videos online about building a Lightning Strike Templar, but they seem to use a red Lightning Strike gem. The only Lightning Strike gem that I can find is green. After leveling it once, I ran out of dexterity to level it again.

Is this build still viable with green gems instead of red? Was it always a green gem build? I've tried substituting Static Attack and it works OK, but still think my Smite/Spark combo got me more bang for my buck.

Any advice would be appreciated.