By themselves they are harmless, BUT to be taken advantage by a bad actor, it could open another attack vector that could used for nefarious purposes. Perhaps to constantly make the network congested through dick pic transactions? There's probably high demand for censorhip-resistant dick pics.
It has always been a matter of whoever is willing to pay the fee is entitled to the blockspace.
The fee market, yeah, but there's real demand for censorship-resistance, and now there's a can be faked demand through Ordinals that NFT "developers" can do to repeat the process of surging fake demand through releasing project after project, like if a series of shitcoin sales were facilitated in the Bitcoin blockchain. The reason for my sarcasm on dick pics in the blockchain is, do dick pics truly need censorship-resistance?
Plus I'm not against NFT, but it will be better to push them off-chain as suggested by n0nce,
https://bitcointalk.org/index.php?topic=5437464.msg61688997#msg61688997