They do help! Im sure there are many people out there that have their reasons as to why you shouldn't use them. I believe that especially as a newer player (meaning within your first 5 years of play) these calculators are not only beneficial to your wallet but also beneficial to your brain. Everything sticks in our brain rather we remember it or not, so after 1000's of hands played using an odds calculator, you can begin to assess hand profitability easier when not having one.
I find they only make the pain of losing with a SUPER PREMIUM hand all the more harder to take. A couple of days ago I was losing with all of my 80% - 97% favored-to-win hands, and would have won had I played the 5% - 10% favored to win ones.