Do you retain the sensation that everything is still wobbling? I would get that after being on a boat for long enough. Though motion sickness never made me feel ill to my stomach, rather it just gives me the worst headaches that require fresh air and time to relieve.
Yes it helps. As in getting you back to "barely normal". (Also you can't do anything around the boat because you're looking at the horizon)
The theory make sense but some people have the thing turned to 11