At a basic level the current fediverse permissions model is akin to quarantine and forced lockdown. It mostly involves a chosen few protecting their communities at the expense of individual freedom. Communities are created primarily around compatible websites. If you disagree with the community policies or feel discriminated against your only choice is to leave the community; at a cost of leaving your content and sometimes your friends behind.
The Nomad permission model is more like being vaccinated; while being able to replicate your friendships and content wherever you desire, whenever you desire. Communities are provided primarily by using membership in federated Groups rather than membership in individual websites. Consequently an individual is more of a free agent and has the ability to choose to be a part of multiple communities.
We also recognise that no single solution is perfect for everybody. That's why we provide both.