The biggest difference between a tool and a machine is that you can leave a machine to complete a task without supervision. A tool need to be in your hands and attention.
For example, the simple task of reheating a food. A microwave is a machine as you can put the food and it will reheat it until it's done. On the other hand, reheating using a pot and a stove requires attention as not to let the food (and the kitchen) consumed by fire.
More significantly, a machine will allow you to do other task while the main task is underway. A tool requires your focus.
In short, machines allow parallel processing while tools requires serial processing.
If you are shorthanded, do look for things that can be offloaded to machine. It can significantly free up your time.