I think you are wrong (2).
Tools are just tools and I've seen many senior engineers who are extremely efficient at what they do—absolutely despise vim/emacs or any other terminal based text editors. They feel more efficient in Sublime/VScode/Pycharm/Webstorm/IntelliJ/Goland etc. They only use vim/tmux only when it's absolutely necessary.
Many beginners just give up when they can't configure these tools around a language properly. I think "repl.it" gives these people a hasslefree way to dip into a language ecosystem and see whether they like it or not.
Once the user has some familiarity with the language and the toolings around it, they make their own decisions regarding whether replit caters their needs or not.