one one hand this would be the highest privacy transaction submission method, because it shares no state with any continuously running P2P daemon that may be fingerprinted or tracked over time by spy nodes

on the other i'm not entirely sure, because if something connects to the Tor network just to drop off a transaction, that may raise some red flags and make it easier to perform some classes of timing correlations against 

 Related comment and pull request: https://github.com/bitcoin/bitcoin/pull/29415#issuecomment-1936003083 

 yes the thing is that this really depends on the threat scenario, which likely differs per person, and per country

my impression from the Tor people has always been "it's good to run the entire node over Tor because that creates noise to hide the signal", but it also has drawbacks, eg the contents of your peers list and other things are very personal to your node and it's easy to expose those inadvertently or indirectly