Not commonly used, but it’s commonly offered as a laptop feature because it’s nearly free to do so. The security it can provide is minimal, but in some cases it’s enough for the job.

If you just need to stop someone from picking up and waking off with a laptop, it’s great. If you need it to resist even a very low skill attack ($10 cutters), it’s terrible.

I don't think newer laptops even have the Kensington port anymore, since they all want to be thinner and slicker.

I used it on my new MacBook Pro at university. My idea was to protect it when leaving in the common room. Too fiddly to insert, difficult to pull-out, scuffed the area around the key slot. After a couple of weeks I gave up. Simply picked up MBP and carried it with me everywhere.

I don't use them. I know a few people who use them in shared spaces because their company requires it as a liability thing. I also know a few people who use them in public places because they don't want to have to worry about their laptop if they need to walk away

Big companies e.g. national utilities, banks often use them. However at the time when I've seen them I had a desktop machine and it was only the sales consultants that had laptops. They all used them.

I've seen them used in public places where theoretically someone could grab a laptop and run away with it.

I bought one to secure our NAS, it's been sitting on top of my safe for 3 years in the box.

Yep, we used them on displayed laptops in the computer store I worked in.