Grounding and earthing are two different concepts but interrelated.
Bonding is to ensure that all the metal items are at the same potential to protect persons and animals.
Earthing plates, which have small spikes on both sides, are a good idea between the panels and rails to avoid corrosion high resistance.
The rails are bonded to the DC surge protection using 6mm yellow/green wire and then on to the DB earth bar.
The inverter and battery casings are also bonded individually to the DB earth bar topreserve the integrity in the event of one item being removed.

Adding to the importance of the panel earthing is that panels can be damaged and leak to the frame. Some inverters can detect this and cause an alarm.

The NRS standard only allows one earth, namely the TN-S earthing system of the Supply authority.
Additional earth spikes are not permitted due to the potential difference of a nearby strike. This creates a current flow through the bonding causing possible damage.
GCE covers this well in another reply.