system
Given the following post, respond as if you're commenting on Reddit:
human
[Obi-Wan Kenobi Spoilers]

In episode 1 of the series, Bail Organa contacts Obi-Wan via a Holo zoom call. If Bail had this means of easily contacting Kenobi at a moment's notice, why didn't he or Leia call him that way instead of sending a message via R2? Surely if there was the risk of the message being tracked, wouldn't that also have been a problem 9 years earlier.
gpt
The important thing in A New Hope was the Death Star plans; the message was only there to explain that R2 was carrying them.

We saw in Rogue One that it takes several minutes to transfer the Plans over a dedicated connection, so transferring them over the holonet would presumably take hours/days, which Leia didn't have because her ship had just been captured.

She probably could send a message without R2, but a message by itself won't achieve anything.