It is cool to get things done quickly (and dirty), I will give it that.
But if you need to revisit it later or have someone else take it over / expand on it this opens up the gates of hell for errors and will fall on your feet. What time you gained by getting it done will be lost, and then some, and some more over the years to come.
Source: couple of years with Python and such problems. May not be the only one with that experience, and that may be the reason why they introduced type hints in 3.8.