If your business model included selling loot, you would not allow NFTs from other companies from which you earn nothing. And if the token is from a previous game of your own company, you can again just use a database without all the complexity.

Exactly. If you need longswords to be scarce, you're going to have a bad time when marty minecraft builds 1,000 longswords and wants to bring them into your game.

The complexity of a NFT system provides a benefit to the company by (A) offloading processing power to people who might be making some money from 'mining' the chain, and (B) not having to run your own marketplace system, while still getting a percentage of TX fees.

If people are mining it, then the processing power required has just gone up by multiple orders of magnitude and is now vulnerable to third parties controlling the mining.