Why Learn Haskell?

Practical reasons Haskell is worth learning:

• It changes how you program — ideas that started in or were popularized by Haskell (immutable data, map/filter/fold, Maybe instead of null, type classes, monads, property-based testing) now appear in Rust, Swift, Kotlin, Scala, TypeScript, and C#. Learning them at the source makes you better in every language.
• "If it compiles, it usually works" — the type system catches a large class of bugs before your program runs: missing cases, null values, mixing up units, calling I/O where you shouldn't.
• Fearless refactoring — change a type and the compiler lists every place that needs updating.
• Real industry use — Haskell runs at Meta (the Sigma spam-fighting system), in banks and trading firms (Standard Chartered, Mercury), in blockchain (Cardano), and in tools like Pandoc, ShellCheck, and the Elm and PureScript compilers.
• Concurrency — lightweight threads and software transactional memory make concurrent code simpler and safer than with locks.

Trade-offs worth knowing up front: Haskell has a steeper learning curve than most languages, because it asks you to think differently rather than just learn new syntax. The job market is smaller than for mainstream languages, laziness makes memory use harder to predict, and the ecosystem, while solid, is smaller than Python's or JavaScript's.