The best solution would be to add wheels as feet which gives you the best of both worlds. It does however add even more cost to an already outrageously priced robot.
The robot that they used is 14k, down from boston Dynamics 75k, and they also have another which is available for 5k which you possibly might be able to do the same thing with it too.
Outragously expensive is not correct if you ask me.
For the other, legs are more versatile than wheels, especially when it comes to uneven terrain.