The crack goes along the shoreline of the bb shell to the right of your picture. You should look for the other end of the crack. It might be behind the crank, seat tubes usually break near the centerline along the side of the tube. The crack didn't originate on the shell. Given that it has propagated onto the shell, I imagine the back side of the seat tube doesn't look that great. Take the drive side crankarm off and take some more pictures. Kudos for cleaning your bike.
I don't think I would ride a loaded tour with your bike, but otherwise it doesn't seem like it would fail in a particularly dangerous way. I have experience with this sort of cracking due to my Teledyne titan. I regret wearing out a front derailleur before i noticed the crack.
Last edited by unterhausen; 08-13-20 at 06:17 PM.