I named it like this, because it has no brain, means cpu, gpu and it could be used to vampirize powerfull (juicy) computers just for gaming. Where the power may only depend of the guest machine. Only thing you should need, a working USB 3.x connector and the autorisation from the owner to use his bios boot menu.
And as you have windows and all your roms onboard, no danger for the business files on the internal hard disk(s). You will not need the password from the owner to be able to use his machine. Based on this thread :
Concerning investment you should basically need one of the new hdd/ssd/ usb3 shells, with integrated hub. Not all hubs allow booting from, and USB 2 is green blood.
I could imagine something like this Orico shell (about 17 Euro) , left and right you plug your controllers and in the middle your Batocera stick.