Another reason this is interesting beyond "Lispiness" instead: implementing a (compliant) Scheme takes on some interesting problems that other languages punt - proper tail recursion, delimited continuations (off the top of my head, I don't know other methods apart from CPS), and hygienic macros.
I really wish lisps were more popular (or, really, popular again). Most people can't make it past the non-Algol syntax, which is silly IMO. But they do also demand more of the user than a typical language.
Their use of metaprogramming doesn't just allow you to extend the language, it really expects that of the programmer. Which means you have to assume the role of language designer to some extent. Learning how to do that definitely feels like a way to level up your skills. But it seems uncommon for people to want to do that.