That's not a bad idea. For this kind of amperage you would need a beefy fuse. Assuming a 58v 500w motor something like this.
https://www.digikey.ca/en/products/detail/littelfuse-inc/089107-5NXWS/5233824
58v x 7.5a = 435w, so this would blow before full power. A 10a fuse wouldn't blow until 580w which would probably be a better option.
The other comments are right, using good components and wires rated for the load, and ensure connections are tight and soldered where possible.
That's a nice guard, I've only seen the half open crescent that is supposed to protect the user from sticking their finger into the wheel.