wittaj - my understanding is the AD410 could be damaged or disconnect/reboot due to being underpowered if connected to a chime without the chime kit during a doorbell press.
I think you meant to say if he would disconnect the chime entirely first, right?
If you don't have a wired chime or plan to disconnect it first, then you don't need the chime kit.
If you do wish to keep your existing chime active - I'm quoting Amcrest instructions here...
The Amcrest Chime Kit is used to regulate the power to your existing chime so that your doorbell will function properly. The chime kit must be installed before the physical installation of the doorbell.