Why?
Saving your logs to media in your possession is not difficult (3000+ backed up here) and keeps them out of the hands of others.
Besides, for the purposes of other people analysing someone else's logs, the output from Phantomhelp i.e. the csv, is generally much more useful than the csv from Airdata.
Admittedly there are a few bits of information available on the Airdata website that Phantomhelp does not provide ( I find this with encrypted Fly app logs * ) but, in general, those bits are not 'vital' to the analysis of a log and some of them are for paying customers only.
If of concern, I think you may find that any logs uploaded to Airdata are shared with DJI. I do not know if the same thing happens with Phantomhelp.
* For Go, Go4 and unencrypted Fly App flight logs there is no need to use either Phantomhelp or Airdata to analyse logs, CsvView and DatCon do a perfectly good job. If you are only interested in csv's of the .txt flight logs then the appropriate version of TXTlogToCSVtool works perfectly well on those Go, Go4 and unencrypted Fly App .txt flight logs.