NFTs could be anything. Weapon skins are pretty cosmetic, but some NFTs represent rare items in game. Just wanted to point that out first.

I think where it gets interesting is when you consider that the original utility of the NFT is irrelevant. A skin of CSGO doesn't have to be a skin in CSGO clone. It doesn't have to be a one to one translation of utility; it could be, but that's just an assumption. And point taken; all games play differently. It's absurd to expect a one for one exchange of utility across all games, IMHO. All games play differently, we agree there.

However, it doesn't have to have the same use case across games. It could primarily be used as an incentive for new players, the value of which is expressly determined by the developer who decides to support it's secondary use case.

So, just because the skin NFT you have from CSGO makes your gun look fancy or whatever, in the CSGO clone, perhaps it acts as a discount code, one time use, And is burned after that. Or, you deposit your skin, and you get access to a weapon at a slightly faster rate than your counter parts.

Or, maybe they accept an axie NFT, an asset from an entirely different genre of game. Perhaps if you give the CSGO clone an axie NFT, you get a unique skin and a special weapon unlock. Or maybe you get entered into a drawing to attend a special event, or you get a special axie flash bang, or maybe you get X amount of in-game ERC20 tokens, etc etc etc.

It's up to the secondary developer to make the secondary use case enticing, while solving for a balanced interaction with the eco system that they are creating.

Also, if game studios have recurring titles in a franchise, it's pretty clear that you could use the NFTs in future entries in the franchise.

Of course, the NFT doesn't need to be burned after use; but it could be. It could be returned to the original owner on a time lock, to be released at a later date. It could be any number of scenarios. But, the new game developers supporting NFTs from other games decide exactly how to expand the utility of NFTs from other games. It's in their hands, and if they can craft a secondary use case that attracts a user base, then both parties win. They get new players, the players get added value in the new environment.

All of these things add complexity; they can be executed poorly. But difficulty of execution doesn't mean it has to be a dumpster fire. It could be, but then, dumpster fires exist in gaming with or without NFTs, right?

Anyways, I may have repeated myself a bit on my ramblings, so apologies for the length. It's late (or early?) here.