It's not the library per se, it's that the library will require all-or-nothing buy in from your entire development team for it to be useful and persistently maintained, similar to how Rambda affected a codebase and a development team.

It's the same effect as adding async code to Python or Rust, suddenly the entire team and the entire codebase (and often dependency choices) must adhere to it.

One of the things I like about Effect is that incremental adoption is easy, and you really don't have to use it everywhere.

You can choose to make a single flow in your application an effect program. Or you can base most of your functions around it. It's really up to you how and where it's used. If you want to use an effect within non-effect code, that's easy to do, too.

You can think of effects like values. The value is obtained by executing the effect. Until it's called, the effect can be placed anywhere, in any function, in a generator, within promises, etc. Once you need its value, you execute it. It's compatible with most code bases as long as you can execute it to get the value. It's really up to the developer how portable they want their effects to be.

I understand, but this is very much like promises in JS. You can pass promises around without awaiting their return values too but async and/or promise code inevitably infects the rest of the codebase. I've never really seen anyone just have promises walled off in one specific module where the rest of the codebase sticks to callbacks.

Passing Effects around will similarly infect the entire codebase, resulting in the entire dev team who interacts with it needing to buy in. Limiting the output of Effects to a single module owned by one zealot dev undermines having it around in the first place and it'll get removed and replaced as soon as that person leaves or gives up the fight.