Advantages of minting NFTs via BTC ordinal inscriptions:
  • artwork exists on-chain
  • the security of bitcoin's hashpower
Now consider: there is nothing stopping the devs of some other blockchain-ish network from adding similar on-chain NFT minting capability, so the first point above might be satisfied elsewhere for cheaper (albeit with less security, though such users might not care about security as much). It is similar to the 'smart-contract-chain' race that has been going on for the last while: ethereum had some success, so chains that have competing features started popping up all over the place. They're more centralized and thus 'cheaper/faster', but the users don't really know/understand why that matters anyways. They just want the features, for cheap.
So I think ordinal inscriptions will be a fad for the most part. It just seems unlikely that users will care enough about them to pay the fees that will come with an increasingly-popular bitcoin, when a (naively) similar feature is available elsewhere, for cheaper.