I use the tool bar every day and I'd say it's VERY worth it. If you do 20 qualifying searches, thats 5 cents a day, on average 30 days a month, which is $1.50 a month. It's up to you if you think that $1.50 is worth it but I do, every penny counts on this this =) To make sure my searches qualify, I usually try to stick with the same category when searching. For example, I often look up different potato recepies and then change words around all about potatoes and recepies. Another example could be travel information, and do 20 searches based on a certain location and things to do there, etc.
As for the extra "money back" or "paid to shop" there are multiple ways to do it. There are a TON of stores that FC pays you back to shop at. For example, Kohls or JCPennys. If you go to their online sites and order online the tool bar has a "click to earn" link to get a certain percent back. I've never used this function but I have seen some pretty good deals/coupons. And if you're already planning on shopping online, why not get a little back for it? Tre is a tab in the tool bar saying "shopto earn" that u can select with a drop down list of categories and then the stores that contain those categories. You can ALSO go to the "fusion cash mall" from FC's home page which will tell you all of the stores that participate with the money back deals and there are coupons, etc there.
One of my favorite things about the tool bar, since I do all the daily offers etc everyday, there is a "quick links" tab that has a link to the paid videos, paid to post, paid to click, your FC account, etc so it's just one click to get to all the popular areas of FC without having to go through ten clicks/pages to get where you want. It also tells you your FC balance.
Good luck! =)
Oh, and to the original poster, this was not a dumb question! Not a lot of people know everything on the tool bar and don't realize how much it can be utilized.