There's seemingly a lot of negative responses to articles concerning constexpr in modern C++ (you can see some here in this thread). I suspect this is partially because there's a general outsized dislike of C++, and partially because typically these articles focus on toy problems where the capacity to run at compile time isn't actually beneficial, rather than cases where constexpr can provide some real benefit towards production code.

Like any syntactic construct in a turing complete language constexpr presents a convenience - in this case the ability to rectify compile time generated data and runtime code paths/data. There are some practical cases I've seen where it can be a real improvement to hygiene (i.e. you can replace a compile time script/program generating data with one unified code base). e.g.

1. Perfect hash generation. Rather than using a separate gperf run you can generate your hashes during compilation of the relevant TU.

2. Format string lookup tables. For fast formatting you can push an index and positional arguments to a queue, and handle formatted string construction in another thread. Broadly speaking lookup tables in general can be generated at compile time rather than static data imported into code.

3. Complex starting conditions for physics simulations. If you have, say, some initial matrix that doesn't change between simulation runs - you can exercise existing code to generate this matrix at compile time rather than needing a separate process run or script.

These approaches are not without their downsides - particularly if the translation units in question need to be recompiled often, or if you're using whole program optimisation - but the benefit of keeping generated data in lockstep with the code consuming it can be worthwhile.

(That being said, I personally find articles like this incredibly edifying.)