Is using onagers a necessity for high level play?

Let me preface this by saying that I am not a serious competitive AOE2 player, as AOE2 is not my primary or even secondary RTS game. But I perform fairly well for someone who plays online sparingly.

That being said, I realized I seldom use certain units. Ever since my negative experience with onagers during early AOK days, I've shied away from them. They are harder to land hits with compared to other units and deal friendly fire. Since onagers are a staple in many imperial age armies, my guess is that I am missing out on an integral part of AOE2 gameplay. I find scorpions are safer to use and equally good for crowd control. Lets compare them.

Common strengths:

• Strong against archers (onagers slightly better)
• Strong against infantry (scorpions slightly better)

Scorpion advantages:

• Cheaper to build/upgrade, thus easier to mass
• No friendly fire
• Lower minimum range, and can indirectly damage units closer than min range

Onager advantages:

• Does not need to be massed to be effective
• Stronger against units with high pierce armor
• Stronger against buildings

Point 1 is offset by the onager's higher cost. In regards to the other 2 points, yea onagers kill huskarls and tarkans faster, but scorpions kill them reasonably fast with their high DPH compared to archer units. It is true that onagers are better against buildings, but that's what we have bombard cannons and trebuchets for.

All things taken into consideration, would learning how to use onagers make a huge impact in multiplayer?