Users could even pay BCH so their content is well hosted (seeded) on IPFS. Since Memo is text it's worth the fee to put it on-chain and have it hosted indefinitely.
Well...even it is on chain, it does not ensure it is hosted forever. It can be pruned.
OP_RETURN outputs get pruned from the UTXO dataset. They are still required to validate the entire blockchain and are therefore recorded with the same level of guarantees as all txns.
