Welcome to Beemaster.
I'm trying to found out the different usages of these two types of scrapers.
As with much of beekeeping, there is not really a right or wrong answer when it comes to hive tools, just preference on the part of the beekeeper. I personally have neither of these tools. I have a standard 8 in. hive tool and a mini J-hook tool now, but I got along just fine with only the standard tool for my first year. The tools in your link have a lot of specific scrapers for different equipment and parts of frames and such, but either style would work well.
Is it necessary to have them both for honey extraction?
Neither tool is necessary for honey extraction specifically; all you really need is something to get the boxes and frames separated. That could be any style of hive tool, or really any generic tool that could do that job, like a large thin screwdriver. I have an old caulking tool that I use in a pinch.