Because in car audio it's all about wasting money.
I just want a simple answer. Will this screw up my amp or not?
Impossible to say. RTFM.
It may or may not. Probably not. No guarantee. Consult original documentation for details.
The thing is, when you give this thing INPUT from the OUTPUT, the INPUT will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT which will route to the OUTPUT which will route to the INPUT --
∞
See the problem? A loop is a bad thing.