1. I usually use repl.it to help friends and colleagues with problems in languages i don't use on a daily basis (since if i do use the language, i wouldn't need a repl). Since i don't really use these language i will in most cases have to refamiliar my self with the language in the process. So i usually find my self google:ling for an "Hello world!" example and pasting it in to repl.it, so in my case it would just feel allot more complete to have repl.it provide a working "Hello world!" example on load.
2. Also, in some language (like C# and Java) there's some boiler plate code that will always exist, and so repl.it might as well provide it, no?
* C#: https://repl.it/Kfwx
* Java: https://repl.it/KfxA/1
* Python3: https://repl.it/Kfws/1