Blood flow to an area speeds recovery. Blood flow to an extremity causes blood to flow through points higher up the chain.
If something hurts or is injured higher up the chain working the extremity past it will speed up the healing process.
Wrist and/or ankle work speeds up your recovery, it improves your ability to heal.
This is a generally unknown reason to train your forearms and calves… healing pumps.
However take note that training the muscles and the joints are not exactly the same thing. The mobility and stability of those extremity joints are also important.
Keeping them healthy will allow you to keep the rest of you healthy as well.