It might be annoying if it asks for ramming confirmation every time you misstep into a wall. Perhaps it would make sense to only allow you to ram through walls at maximum momentum after which your momentum would be reset to 0. You'll need a bit of a run up
Actually I'm not 100% sure, does momentum increase ramming damage? How is ramming damage calculated at all actually?
Also doing this for extended tunnelling would be weird... I guess if you needed max momentum for it to work there is something stupid and gratifying about taking multiple run ups to smash a tunnel into existence.
Me Cogmind. ME IS UNSTOPPABLE!!!