If any one's looking for the answer to why it's not recommended to edit library imports - when you import collections from the library, you can receive updates whenever the collection author publishes a new version. These updates might include new exercises or improvements to existing ones. However, if you've made your own modifications to the collection, these personal changes will be overwritten when you update to the newer version.
It's mentioned on the faqs page - https://www.captrice.io/user-guide/faqs.html. Missed updating the link. Will push a fix shortly.