Steam Deck

Yes and no. When I got my OLED is was so light but after a JSAUX modcase, it sort of lost that feeling. That said, I'm all for protecting my devices and I have a toddler, so that's me.

When I purchased the original Deck, I had it sitting on my desk in my garage with some headphones plugged in and my dog, who was under the desk, got up and bumped the cable with her head. The cable startled her, causing her to panic and jolt, catching the cable around her torso, and yanking the Steam deck off the desk. Dog is now in a panic as the flying Steam Deck crashes into the cement floor behind her, bouncing and skittering across the ground about 6ft or so until it came to a rest. Now, all of this happened in llike 2 seconds, so there wasn't much I could do. It was basically new out of the box, but it took that incident without issue. That was a a few scrapes along the back/side, but no damage to anything else. Has run fine since.

All that to say that it's tanky in its own right, but your mileage may vary. I lucked out I think, but even a case won't save the screen from an ill placed drop onto a rock or something like that.

I have the standard Spigen case on mine (not the thin fit pro that you linked), and I like it. I have large hands, and find it quite a bit more comfortable than the caseless deck. I've heard of decks popping open at the seams when dropped on their sides, and having a case will protect from that. You also want one that has a ridge that sticks out above the L1/R1 buttons to help shield them from a drop, although it's not possible to protect them from every angle. The case you linked specifically doesn't have any protective material there, so I wouldn't get that one.

The other case I have hands on experience with is the JSAUX mod case, which my son bought. The hand grips are more comfortable than the spigen case, and the front clip cover seems super nice. Spigen has always done an amazing job protecting my phones from drops, and I don't know if the JSAUX mod case will give as much drop protection. But in terms of case feel and features, it's clearly nicer than the standard Spigen case.

The Steam Deck isn't a device I would use while standing or walking around, so the risk of dropping is slim. Also, in case of a fall the risk of damage to triggers and joy sticks is large, which wouldn't be protected by a case.

I did put a screen protector on, altough it was mainly because I want a matte display as I use the Deck in places with sun light.

I ended up buying the Killswitch case from Dbrand. It's sturdy, the lip of the case rises up to cover the screen edges and it has a hard face cover while traveling. I normally leave it with its kickstand on various locations to charge for when I need it. It was an added weight but I don't notice it anymore, and I enjoy the textured feel of the case.

Personally I wouldn't really want to add any extra bulk to my Steam Deck. The case you linked also only really protects the back of the device, which shouldn't be too susceptible to damage. Wouldn't do anything to protect the screen, buttons or internals. If my Steam Deck's shell ever does break, I'd just buy a replacement one from e.g. JSAUX.

I bought a thin case with a protective front panel that clips on magnetically. That is enough to protect it when thrown in a backpack without adding noticeably to bulk.