I think the point of "specialty gadgets" is that there are a plethora of "travel items" that you haul while traveling, but never would need at home. It is of course personal preference, and I travel with a couple items others may think crazy, but it is easy for many to get carried away with "ooh, that neat and looks like it might be handy" and never gets pulled out of the suitcase, or is for only very limited use.
Things I looked at, maybe even traveled with, but have decided to leave home?
-Neck Pillow and Over Ear Headphones, bulky and are mainly only for the flight over, then you lug them for the trip.
-Lots of things for laundry (clothesline, detergent, washing bag, etc.) My compromise anymore is a few detergent sheets, but the sink, a little liquid soap, and any available object to dry a few things works. And that is really only for a few pair of underwear or to deal with a stain, otherwise, I strategically get an apartment with a washer or hit up a laundry.
-Any "Boomer tech" things I used to do or haul, that my phone, e-reader, or laptop can now do. So no guidebooks, books, maps, paper printouts, camera, video camera, translator books or menu decoders, the list really could go on.
-The "Day Bag Load", some people wandering the streets look like they are on safari, hauling a bulging day pack. Usually filled with the Boomer Tech items, but food for a few days; a couple gallons of water; umbrella, parka, and options for every variation of weather; maybe a tent in case you get stranded near the Trevi Fountain. I only jest a little bit, but one really does not need all that in an urban environment. I found out water and drinks are readily available, if I feel the need for a snack, I visit a bakery, or a store and find something different and interesting. The weather? I take my chances, I'm drip-dry, or can wait out a shower having a beer. Now when I go out for the day, I have my passport, my phone, and an ultra thin wallet with just a credit card and a little cash. It is absolutely liberating.
What do I haul that may seem unnecessary? I have my vices, I haul a flat sheet, I get hot at night, and duvets are the bane of my existence. My wife has grown partial to a small USB powered fan, she sleeps better with some air moving and white noise. I also pack an outdoors "Drybag" probably several liters in size. It is good for packing wet/dirty clothes, just as a pack sack, and can double as an ice bag for drinks or food, or to take to the beach. I also purchased a multiport, high wattage, USB charger with the Euro type C plug, so no adapter needed for most travel.