I don't think we should likely remove this feature.
We provide users a choice in terms of which container implementation they wish to use, and adapt certain features we feel should be common and work the same between implementations (invokables and delegators, primarily). However, people choose container implementations based on features they provide outside basic compatibility: speed, ease of configuration, extensibility, etc.
Disabling this particular feature makes it harder for end-users to configure Pimple if they want to use Pimple-specific features. Yes, this feature largely replicates what delegators do; in point of fact, however, the way we implement delegators within Pimple is as extensions!
Revert #2
@weierophinney said (https://github.com/zendframework/zend-pimple-config/pull/3#discussion_r156503536):