a very useful correction here: https://nitter.net/mononautical/status/1725813952377127375

bitcoind does rely on the mempool for fee estimation.

the estimatesmartfee algorithm works by tracking how long transactions in different "fee buckets" wait in the mempool before getting confirmed.

which means it needs to see a representative sample in the mempool. 

 though would missing ordinals really affect fee estimation as long as there's an adequate sample domain of transaction fee sizes? (fyi this is Signoi from RaspiBolt)