Are they that useful, though? I have them on my dining room table and they're just annoying. It's difficult/impossible to get enough torque by hand to prevent them from quickly coming loose again, and they hurt to tighten/loosen by hand.

I think we rarely see them nowadays for these reasons. Nyloc nuts tend to be the norm for things you rarely want to come undone again. On bicycles the quick-release skewers have replaced them. I can't actually remember buying anything in the last twenty years that utilises them.

Your table hardware was likely optimized for profit and not usability. Replace them with larger nuts or knobs.

Bicycles are unfortunately losing their quick releases because of the disk brake incursion and the increased risk of wheel ejection when not properly installed. Plus carbon frame builders want to skimp on robust dropouts to make up for the weight gain of the heavy hub and brake setup.

It was optimized for profit, highest prices, lowest possible cost. The very lowest possible cost.

Wingnuts are strong, and you can pry them on, and off with a screw driver.

I made a portable shack with carriage bolts and wing nuts. When it came time to break down the wood has all swelled with moisture... so the screwdriver loosed them all.

I have had several accounts in the past, just for fun. I'm a complete newbie, but enjoyed many articles and commented on them. I was constantly downvoted (or whatever term is used) and I was many times just innocently asking honest questions. I feel that most of the people here ARE childish and can't relate, and therefore impose their 'powers' of banning and downvoting. After a year of all that childish behavior on here, I just closed my accounts and left. I am just a very curious (and I think I am intelligent) retired senior aerospace engineer. I was just so rudely treated here that I couldn't fathom the reasons for it. I am just too ignorant of this 'new' culture, I guess...

I use wingnuts on my CNC which is full of vibration and never see the nuts come loose. That problem may be specific to your table.

Nylocs can only be reassembled a few times before they stop locking, and many people use loctite to address the backing-out problem.

Wingnuts against softwoods basically suck. the wood fibers just keep compressing and you keep tightening forever.

that's what washers are for.

specifically, fender washers. Nice thick ones.

I used to work in the events industry as a tech, so many of the mounts for speakers and lights have wing nuts, there are probably days where I have undone of a thousand of them.

So they definitely still have uses!

They are good for stuff that you do want to come undone again.

I don't really see the problem with that. It doesn't lessen their utility.