Sure, in our indexing design we chose an op_return padded length that conflicted with more common op_return uses for this reason. Moving it into keys is obviously better hiding. But the rest is the same, the recipient still has to scan a huge number of txs with ec mult cost. But that can now be vectorized in GPUs, which has made it reasonable again. I dropped this index in bs in part because of the O(N) cost of every query. I talked with Craig about it last night. I think we could pick op the additional dependency conditionally for public deployment, it's pretty clean. But yeah, for personal use it's a much easier performance problem.
(edited)