[Too]

Hard to give a concrete example but you can end up in dependency deadlocks, with combination of packages that require new features vs packages that don’t work on newer versions.

Mostly it’s useful right after a new release where prebuilt wheels aren’t available for all packages yet and you have users who may care or not about this.

If you only have single requirements file, you get forced to choose which platform to support. With multiple, you can break out if needed. These breaking changes and deadlocks are rare. It’s still good to have an escape hatch.