When I publish something under MIT/ISC, it's generally, I wrote this to solve a problem/need, if anyone else finds it useful, cool. Use it for whatever you like.
If I'm writing something I intend or might intend to monetize later or otherwise don't want to have privatized, I'll probably reach for GPLv3, AGPL or a different license. The less "whole" a thing is, the more likely I'm going to use a more permissive license than not. Libraries or snippets of code are almost always going to be permissive at least from me. This includes relatively simple CLI utils.
If I'm writing something I intend or might intend to monetize later or otherwise don't want to have privatized, I'll probably reach for GPLv3, AGPL or a different license. The less "whole" a thing is, the more likely I'm going to use a more permissive license than not. Libraries or snippets of code are almost always going to be permissive at least from me. This includes relatively simple CLI utils.