dnd 5e – Is animate objects overpowered?

I am new DM just running around 10 to 15 times. I have an experienced player and he plays as wizard.

He is casting animated object so that he can attack my mage or weakling.
He moves 20 feet and he cast animated object on 10 coins. And the coins can then move a further 30 feet. He said it can and yes I already check it. My mage enemy didn’t have counter spell, dispel magic or fireball (AoE).

That why I am asking are animate objects a bit overpowered?

Since they can summon 10 of them (coins), and they have a speed of 30 feet, attack bonus, HP, and attack opportunity?