Given it's intended to be a permanent fixture in the side of your laptop, at the size of a (keyboard) key I'd say it's pretty big, yes.

Add that to the one-and-a-half key-sized optionally permanent part (unless you're going to buy one for each cable, it's fixed until you need the safety feature) and it's a huge thing sticking out of the side!

To be honest, I question the usefulness anyway - I've pulled my Macbook Air off a table (accidentally) by it's MagSafe power cable before, and trying it deliberately now it only works with vertical movement. Side-to-side or directly 'out' it just moves my laptop, even as short & and sharp as I can.

If I stepped directly on the cable it would be such a directly-out movement; if I tripped, a side-to-side one. Unless my laptop was positioned perfectly such that the MagSafe hung over the edge of the table, and I trod directly down, I can't imagine how it would have its intended effect.

I use it all the time for un/plugging deliberately, but I can live without that, and as above with this Kickstarter product without buying several I'd have to leave the whole dongle plugged in anyway, so any deliberate dis/connection would be a normal un/plug motion.