Engineer here, I just use whatever's convenient. It's handy to know both.
That said, I did confuse a poor coworker of mine this week when I was using bar for tank pressure and psi for the safety reliefs. That's totally on me though.
To be clear this was a conversation over the phone, not a tech review or something. And I was explicitly naming the units, it was just jumping all around that had him confused.
Official documentation and programs should always be explicitly clear on what units are being used, especially pressure.