Yes. Let's say the player moves 10 pixels each tick to the left. That's at 60 fps. Now let's say the frame rate drops to 30, that means he will be walking 50% slower, because the event will only run 30 times each second instead of 60. To counter that, you multiply the speed by delta-time, which will be low if the fps is high, and high if the fps is low, bringing consistency to the game.
I was supposed to have linked this tutorial in my previous post, but I got it wrong
Not to forget you can't expect the game to run the same way at say, 20 fps. If it's that low you can say the game is unplayable