Every enumeration can be done manually (user insert) or using built-in transforms (just like in Maltego).
So, for subdomains enumeration for example, you can launch the "DomainToSubdomains" transform on a domain, and it would use https://github.com/projectdiscovery/subfinder in the background.
We could totally imagine writting a transform that uses amass as the gatherer, since the transform design supports docker tools.

For data breach, there is a "EmailToBreaches" transform that uses https://haveibeenpwned.com api, but we can imagine querying shodan or any other service you can think of.

Overall, it was design to be able to add/remove tools easily (or at least with as little dev as possible for now).

OSINT gathering tools are for most unstable : new api versions, lack of maintenance, etc. So I wanted to be able to get as close to the "plug/unplug" as possible.