This makes sense for community leaders to also be moderators, however seems like there can be a potential conflict with that.
I don’t have a lot of background in moderation, but in theory for moderators to be good seems that it could help for them to be a step back from being a community leader so that they can see clearly the perspective of new people on even ground with long-term members.
That can depend a lot on the kind of site and community and what it is for.