Templates are semi-accidentally Turing-complete. They were intended for writing compile-time-generic, run-time-concrete functions and types - but it turned out you could use them, along with the overload resolution mechanisms, to compute things. The Turing-completeness involves recursive use.

Computing things using templates is not intuitive. Many of us have gotten used to it - but that's because that's all we had for many years. It's a different sub-language within C++. As constexpr capabilities widen, we can avoid "tortuted" templates and can just write our compile-time checks and figurings in plain C++ - more or less.

Sometimes, enhanced language features in C++ allow us to actually throw away and forget about other existing features, or at least - complex and brittle idioms using existing features. Like SFINAE :-)