Answer
SFINAE with std::enable_if constrains templates by making invalid substitutions silently remove overloads—powerful but cryptic and hard to read/maintain. Concepts express the same constraints declaratively, give clear diagnostics, participate cleanly in overload resolution (more-constrained overloads are preferred), and are far more readable. Concepts are the modern replacement for most SFINAE.
// old: template <class T, std::enable_if_t<std::is_integral_v<T>>* = nullptr>
// new: template <std::integral T>Real-world example Rewriting enable_if-heavy code with concepts makes constraints readable and error messages clear.