Former aflac rep here. How worth it the plans are depends a lot on your personal situation. You have to be careful with some of the reps, they hire constantly, so they may not always be knowledgeable, and not are all are as ethical as i tried to be. Let me give a little bit of a rundown of how the plans may be worth it. For the average person with an accident plan or something alot of it comes down to how prone you are, and how tight you will be stretched if theres a problem. If its not money youl miss being a few bucks a week they do have a point. If you have 1000$ deductible and typically live off your next paycheck and dont have savings youl be pretty screwed if you end up in the hospital overnight. But that is really based off your financial situation.
As far as im concerned each plan has a type of person who is crazy not to take the plan at a group rate, everyone else is situational.

If you are an active person, and play sports, or you have kids who are playing football or something where theyre at risk, then you should get an accident plan no ifs ands or buts. Just get it. You'll thank me.
If you are a single income family, and a rep comes through offering short term disability, and you dont have a really substantial emergency fund, please, get disability. In NY, the state disability maxes around 170$/week, taxable. So figure 130$ a week, which in new york, is not liveable, so if you break your leg, and cant work for 3 months, that is what you will be using to provide for your family.

If you have a history of cancer in your family, and are high risk, or if you are a regular smoker, you really should look into the cancer plan. I know it can be bleak to think about, but Cancer treatments can often be out of network, and expenses get ridiculous so I get nervous about this one.

IF YOU TAKE A PLAN. FILE YOUR CLAIMS. I DEALT WITH PEOPLE EVERY YEAR WHO JUST DIDNT REMEMBER TO FILE FOR OVER 14 MONTHS AND THREW AWAY THOUSANDS IN CASH.