The fundamentals of CS courses in my undergrad program were taught in Racket (with HTDP). At the time this seemed very impractical, because I already knew Java and just wanted to write useful apps.
But as I've progressed in my career, I've come to appreciate how it helped me develop a strong foundation for reasoning about programs and their underlying logic (in any language) that continues to serve me to this day.
If I was approaching this outside of a structured curriculum, it would be hard for me to justify this long-term intangible benefit relative to being able to move quickly to write something interesting and useful. And I think writing interesting and useful programs is the best way to motivate oneself to keep programming. So I can't strongly advocate for this approach. But I do think there are some worthwhile benefits.
But as I've progressed in my career, I've come to appreciate how it helped me develop a strong foundation for reasoning about programs and their underlying logic (in any language) that continues to serve me to this day.
If I was approaching this outside of a structured curriculum, it would be hard for me to justify this long-term intangible benefit relative to being able to move quickly to write something interesting and useful. And I think writing interesting and useful programs is the best way to motivate oneself to keep programming. So I can't strongly advocate for this approach. But I do think there are some worthwhile benefits.