Do people still eat animal organs for fun and not because of a diet they read on a sketchy website?
I have done from time to time, though not that often. I am a big fan of making a thing called Sarapatel with a pig's organs. The heart, kidneys, liver and tongue in particular, not much of a fan of the lungs. Par boil them in salt water with a dash of lemon and vinager till firm, cut up in chunks and add to ground pork meat with loads of spices and assorted things I want. Sometimes I make it more sauce heavy to be spoon eaten, other times drier and crumbly. Pretty good.
However I can speak for most of Brazil that there are 3 main items of offal that are quite popular still.
First one is ox liver, cut into thin sheets which is well seasoned and fried. Not really that popular but reasonably so done with a bunch of sauted onions alongside it.
Second is ox tongue. Reasonably popular, loads of places sell them. You can buy them raw to make yourself, having to do the final cleaning at home and such or you can just buy it ready to make already done by the market butcher with bacon/sausage/carrot stuffing and ready to put on the pressure cooker for preparing. Pretty good stuff and the meat comes out quite tender and flavorful. Pic is kinda shit but it's the best one I found of a traditional style of it.
The final one, undisputed king and so popular most people don't even realize and connect the dots it is actually offal is
chicken hearts. They are a staple of Brazilian barbecue. It's just a fucking good piece of meat from a chicken, it has a much stronger flavor than the rest of the animal being more like a duck than a actual chicken and the fat on it makes it deeply savory. It's extremely common on any even just decent BBQ place and absolutely a must in buffet BBQ. It's good no matter how well done too, meaning if you arrive as the restaurant has just opened and the hearts have just barely warmed it is tasty but if you are eating the last ones in the skewer that are shriveled up and well done they still are good tasting now less like duck and more like crispy bacon or something, which I suspect is part of what makes it good for buffets.
The most notable use is on barbecue but you can stew them, fry them, bread them... Just good multipurpose cut they are. Fuckers are so popular that we actually have trouble keeping up with demand. Despite the billions of chickens we produce and slaughter for export in Brazil producers are almost unable to sell any to international markets because our own national market will buy up ALL the hearts, the the point in the south where BBQ is the most popular they sometimes have to import to keep up the demand. Thankfully no one else has caught up and the rest of the world remains sleeping on chicken hearts, so we are safe for now. Hopefully the chinese don't realize they are good and start buying the same way they did with all our chicken feet. (Though to be fair the chinks already liked chicken feet, they just woke up to the fact we did too and ours were better)