For those who are curious, I googled Kontrol Freeks and it turns out they're analogue sticks that go on consoles like the PS3/4 and the Xbox 360/One.
To answer the question, no they don't. In fact they can harm your thumbs due to the size. Your thumb tendons aren't supposed to reach as high as the Dual Shock 3 demanded, and these analogue sticks - which go on top of the original joystick - are much higher. The grips can help because it took Sony 3 consoles to realise that their controllers suck eggs with their analogue sticks (concaved sticks on the second design of controller for the PS1 was the best design choice they made in their lifetime). So if you're like me and can't stand the Dual Shock controller on a PS3 or consoles prior to it, these are for you, but mind your thumbs.
Both the Xbox One and the PS4 have concaved sticks and thumb grips which is what Kontrol Freeks are boasting about with their own products, and they're perfectly fine as is. So paying an additional £10 for something you've already got and are fine with is silly. Also, these controllers will have been made with FPS gamers in mind because the end of the genre isn't in sight, and testing would tell Sony if players were satisfied with the controller design during gameplay of different genres.
If this was too long, here's the bottom line: No, they don't help with gameplay. They're bad for your thumbs and are another useless gimmick to make you think you're a pro or you're in need of more grip and sensitivity in move speed. Don't let accessories dictate the way you play - a game should be all about your own skill, and the fact is they are.