I really thought both of those would have been great items to have with you. I have heard of others recently saying their Leatherman's are dead weight. I see my packing list needs revisedMy most useless bits of gear have been a Leatherman, which i only ever used a handful of times for the knife, and one of those solar rechargeable battery packs, which doesn't recharge fast enough to be worth it over a regular battery pack. Both of those were gifts, though, so better than nothing.
Stuffing newspaper inside wet shoes will dry them out in no time. Years as a bike messenger taught me that...I love my foam sleeping pad thingy. I don't use it for comfort. It's basically no different from sleeping on the ground. I just use it for insulation. I like that you can get it wet and it'll dry off no problems.
Personally i can't stand inflatable mattresses, they always seem to leak or they're too springy or "gappy". I'm more comfortable on the ground. I'd only get one if i was going to sleep somewhere extremely cold and was forced to have the extra insulation.
My most useless bits of gear have been a Leatherman, which i only ever used a handful of times for the knife, and one of those solar rechargeable battery packs, which doesn't recharge fast enough to be worth it over a regular battery pack. Both of those were gifts, though, so better than nothing.
Something i spent my own money on that wasn't worth it was good headphones. They were useful when i was housed up and DJing or writing music, but they're dead weight when i'm traveling because listening to music is either not worth wasting the battery or (on headphones) it's a distraction/safety hazard.
The other thing i carried around for years and definitely wasn't worth it is a second pair of sneakers. My theory was when the first ones get wet i'll swap them around. That worked, but it's much better to get wool socks that dry faster than cotton and a thin hiking/trail running shoe that can dry itself off at least halfway overnight, or while you wear it.
I have three panels they all connect up it works well ive found the bendy panels dont hold up as well as the hard ones and yeah leatherman do have a tendency to rust thats why i coat my army knifes in a sealant it works well since i hop and can be in the weather for days on endI think it depends a lot on the type of traveler you are and what other gear you need to maintain. In my case, i've never had a big mechanical bit of gear that i need to fix or jerry rig. The tools are too crude to work on anything i have, like a phone, tablet or even a bicycle (i have a separate mini toolkit for that). It might come in handy if you drive a vehicle with a motor or need to cut through fence wire or something? I dunno. I switched to a fixed blade knife which takes up more space, but it's lighter and when i do use the knife (which is rarely) it cuts much better. The other thing about my Leatherman is that it rusted/corroded a bit after being at sea, which was kind of annoying.
For solar i think you're better off going with a foldable or bendy set of multiple solar panels that you can use to charge anything rather than just those battery packs which only only have one panel on them.