There are two things that need to be clear to understand the difference between SECockpit and other keyword tools.
The first is that many keyword tools check the number of results returned by Google, when a keyword is searched for in quotes. You can go ahead and search for any keyword in quotes in Google, and you'll see that there's an estimated number of how many results Google found in total.
Many tools use this number to determine the competition difficulty of a keyword. The idea is that if the number is lower, you have fewer competitors and therefore it's easier to rank for this keyword. Unfortunately, this number has no real-world correlation with how easy or difficult a keyword is to rank for.
The second thing is that some keyword tools offer a "closer analysis" of a keyword. They fetch the currently top ten ranking websites and analyze those pages, the number of backlinks to those pages and other SEO metrics. This is the true way to determine SEO competition: you need to take a close look at those factors that make the top ten pages rank where they do. You need to find out if they are well-optimized pages, whether they are pages on authority sites or not and how many backlinks they have.
The downside is that this kind of analysis takes quite a long time to complete. A typical desktop-based keyword tool will probably need a minute or two to gather all this data.
SECockpit gathers all this data, for all the keywords it returns and it does so at a rate of hundreds of keywords per minute.
And that's it, really. What you see when you look at a list of keywords in SECockpit, with the competition bar displayed, is the equivalent of what you'd get after running keyword analysis, one by one, on a desktop tool for hours on end. But in SECockpit, it only takes around 30 seconds to generate the whole list.