I just completed a triathlon last weekend. It was fun. I enjoyed it very much. There were all kind of bikes out there. Time trial,road,mountain,hybrid, made out of Carbon fiber , aluminum,and steel.
I think your bike is different, unique, kinda quirky and will fit right in, completing a triathlon. I grew up riding dept store bikes and never had a problem braking or anything that made it unsafe to ride.
If I were you I would clean it up adjust gears,brakes, and the like, and make those cables neater.
You stated you completed a triathlon, was it on this bike?
Post more updated pics.
Don't forget to have fun and go like hell.