Mickey Mouse may be very entertaining on screen, but when you find mice and rats in your own home, it is often not quite so funny. Mice and rats can also create health and safety hazards, so they need to be dealt with quickly and effectively.
You may not wish to kill them with poison for obvious reasons. First and namely, is out of humanity, but another less important reason (although for health and safety reason, can end up causing an issue) is that they can create problems such as odour and mould if they get caught in unreachable places in your home and start to decompose.