from monster import *

Using from <module> import * is discouraged because it copies everything from the "<module>" namespace into the current namespace. This muddying of the namespaces can cause collisions and side-effects. If two or more modules were imported using "*" there is no telling where objects come from. If both modules use the same name for an object the second import would overwrite the first import.

The preferred way is to import just the objects you need using "from monster import Monster".

Additionally, as programs grow in complexity, a more general whole-module "import monster" is preferred so inside the code you would type "monster.Monster" to reference Monster. Which makes tracking objects origins easier. Certain well know module objects, such as datetime.datetime are imported as from datetime import datetime, but for lesser know packages import just the module.

It's not about saving keystrokes, but rather about keeping your code clean and organized. While the any code makes perfect sense to the original programmer, to others, or to the original programmer months later, things are much less obvious.