Remotec ZFM-80 Questions

I’m new to the smart home technology. I’m wondering if someone can provide some clarification on the remotec zfm-80.

Does this require any additional components to work as a smart remote, other than an app? Can I just link it to an app/account, then sync it to my google home? Or do I need a hub of some sort?

Why would i need an external switch hooked up? Doesn’t the button the this product act as a switch?

Sorry for the confusion. Thanks for any help.