Yes, because

In the first kind of language, the thought process is basically: I have the flow of execution, starting at the top of the file. If I want to make a library, I should build the things I want to build, then get out of the way.

Note the “I have the flow of execution”, and the “if I want to build a library”.

If you just want to build an executable, do as you wish, you already have the flow of execution.

If you want to build a library, make the relevant classes and functions and get out of the way (i.e., no IO, no long-running tasks).

If you want to combine them, use the main name check - or, make a package and do entry points that way. Either way works, because both can fulfill the goal of staying out of the way of those importing this as a library.