Why should I bother to convert tests from REPL? I use REPL for experiments along with testing. When I done experimenting I also done testing. When I'll return t

Why should I bother to convert tests from REPL? I use REPL for experiments along with testing. When I done experimenting I also done testing. When I'll return there, it would be for another experiment, significant part of my previous tests won't run again. Also, I work mostly with pure functions and strong type systems. Those functions won't change their behavior if I change something in the system. These types won't let slip something bad that is hard to find.