Apart from reducing the threat of government control as discussed above. Non mining full nodes provide strength to the network, allowing other nodes to synchronise quicker and easier, but also voting power, as we are seeing here in the Core vs Knots debate.

Full nodes are voting by moving to Knots that they have lost faith in core. These are public metrics the core developers will be aware of. If it gets to a critical point, whereby Knots has more than 50% of the active nodes, core has lost its ability to support the miners adding things node runners don’t want on their disks.

If Ocean are the only mining pool creating blocks that the majority of node runners are prepared to add, we have 51% control of Bitcoin. The infamous 51% attack, without requiring 51% of mining power.