The main reason I didn't merge privatebroadcast to
@BitcoinKnots, was that I judged it to be underreviewed and prone to bugs.
Since Core merged it in January, there were several followup fixes proving I was right, even before 31.0 was released.
They went ahead and released it anyway.
We have become aware of a privacy bug in the -privatebroadcast feature, newly introduced in Bitcoin Core 31.0, that may cause the originator’s IP address to be revealed to the receiving peer under certain network conditions. A fix is forthcoming and will be released with 31.1.