Yeah to be fair if you do all the homework with LaTeX there's no reason not to set up your machine.
I've even heard of someone who even used it to take notes in class... Honestly I wouldn't dare to try and learn that!
But yes, that's when the macros and possibilities you don't have on overleaf becomes really good to have.
I wouldn't call it sharing... don't know about you but where i live you pay less taxes when having a child, and i've never seen a service make you pay less to share it.
That's taxes. Life in general though, well that's literally sharing.