So I've got a bit of a selfish reason for making this post aside from starting an autistic debate about the back end of RPGs again. I'm just playing around right now with learning inventory mechanics and learning them.
Every time I look at grid inventories, yes they're sometimes quite nice visually laid out and everything and it lets you sort stuff well as the player when they're coded properly. At the same time though from the player's perspective I have never really cared much about grid vs list I played the hell out of Skyrim and Fallout 4 and I actually quite enjoy the list inventories because you can quickly scroll down clicky click your way through stuff and you're done whereas with grids you're dragging and dropping things constantly and having to split items in a fairly tedious way.
My main point with this ramble is though thinking about inventory design does anybody here actually care that much about what the inventory screen looks like if it's clean and usable? I bring this up because if I choose to code a list over a grid in my projects that have inventory systems it's a remarkable difference in the work load, lists are definitely easier to deal with and take less code compared to complicated grid systems if all you want to do is let people pick up and drop stuff or equip things and there's not much else going on.
For extreme examples, think Skyrim vs Diablo 2 in terms of how they have their inventories. Been fed up of bloated RPG after bloated RPG being released so I'm going to play around with these ideas for the lulz while I think about my other work now my RL garden stuff is calming down.
A bit of a cop out answer from me, but I'll at least tell you why I don't think it matters much, and should just fit the game's overall feel.
Grid if you've got a lot of stuff that someone took the time to make pictures of, or you can easily see it rotate or something nicely in your inventory. Which probably takes a lot of time and effort to do all that. Which is appreciated most times. Just being able to inspect the things you pick up, so you can look at the details. That's always fun.
However, inventory lists are fine if you can quick swap between food, healing, armor, weapons, etc on the fly to make finding things easier.
It really depends on how much time and effort was put into making things look cool in the game, and how much detail it has. If it's a pixel game or a low poly game, a list inventory is fine. Maybe add little icons of what the items type is. Such as a sword/gun icon for weapons, suit of armor for armor, apple for food, etc. If items fall neatly into the above list of basic things you're bound to come across.
But if it's a 3D game, and a lot of time and care was put into things looking really nice, it might be fun to see it in closer detail in your inventory.
If I wanted to do an inspect in a list I could just do what Skyrim does but less janky and have a right click inspect feature or something to let you look at a game model. I actually don't understand why devs don't make use of lists more often because they're so much easier to work with code wise. Probably just going to have an experiment with it now I'm getting more and more time back.
I'm also thinking about what kind of RPG style I want to play with so much to get on with while I bounce between my projects lol. Think I will mess around with this, it's going to give me lots of practice for UI which I need to get better at.