"Connection mode" doc page unclear

[igal1c0de4n]

From https://vuex-orm.github.io/plugin-graphql/guide/connection-mode.html#mode-2-nodes :

This is the preferred mode and used for the example queries in this documentation.

This section is a bit unclear.

Specifically it would be useful to understand why this is the preferred mode. What are the consequences of not using it?
Lastly, assuming I would like to modify my graphql server to support connection mode 2 (it's a nodejs Apollo):
A link to a doc page re how to support it would be useful. Or a link to a project which implements graphql responses according to the expected "mode 2 nodes" structure.