The intro suggests that it’s for “unstable networks.” The protocol is required by the HomeNet project [0, 1], so residential networking (possibly including IoT) seems to be one application.

[0]: https://datatracker.ietf.org/wg/homenet/about/

[1]: https://datatracker.ietf.org/doc/draft-ietf-homenet-babel-pr...

Take a look at the document "Applicability of the Babel routing protocol": https://tools.ietf.org/html/draft-ietf-babel-applicability-1...

it's used for mesh networks (but can also be used for other applications) - some freifunk communities in germany use it and there is ongoing development to port the most popular mesh firmware called gluon to use babel as it's a layer3 mesh and gluon is using a layer2 mesh (using B.A.T.M.A.N) - layer3 scales better because with more nodes you have a noisy switch on layer2.

Fascinating stuff - if you want to learn more about babel here is a technical talk from the developer: https://www.battlemesh.org/BattleMeshV8/Agenda?action=Attach...

AFAIK a main goal is a routing protocol that handles mesh networks well.