Grounding (earthing) are made up pseudoscientific nonsense. It does not work. It is mostly supported anecdotes and testimonials, which should be a red flag. If there is any benefit to be gained from it, then that claimed benefit is probably due to...
There is none. A lot of claims have been made regarding the evidence for barefoot over wearing shoes, especially in the context of running. There was quite a fad while back towards barefoot running with many and multiple claims about the science...