Clearly, effect systems, as we know them today, are very heavyweight, and not worth the effort in the small. That's not controversial. But we have to present the ideas to beginners somehow. Those complex types come into their own in (some) large-scale programs, and especially as large-scale programs evolve, as they are being changed by programmers other than the original authors. (Not all programming tasks may be suitable, see the article on Rust for games programming that's on the front page RN.) All that said, the whole point of the article, and the research on direct style effects is to make effect typing much more lightweight. Effect types as we do them today metastasise along the call graph, and that is a big problem (this is also why Java-style exception specifications are considered a mistake). Direct-style effects essentially use implicit arguments, as popularised by Haskell and Scala, to hide much of this complexity. Whether this experiment will succeed, or direct style effects suffer from other problems is unclear and we have to wait until we have enough experience with them. And that can only start, once there is a language that implements support for first class direct style effects.

The article suggests that this is coming to Scala, and I'm looking forward to being a guinea pig.