Sorry: PPT=Powder Paint... in text mode. LOL
I like the idea or Steel It on the chassis and even more so on the suspension parts since most seasoned desert racers crack check/inspect those parts frequently and I understand you can mag or spray crack check them w/Steel It and cracks will show. But then our cars used to come down to bare chassis/plumbing and wiring for every race.
On the Canned Ham we have, we opted to paint the cage black to match the OG chassis parts left and will Steel It all the suspension and steering. Side benefit of Steel It or normal Paint as has been mentioned: You can clean it off easier and repaint if you add tabs, make a repair or change things where as with Powder Paint, it's a pain in the arse...
FYI, We had a 16 car we redid a roof on that was already PPT'd when we bought it. We bought the matching Cardinal rattle cans and redid the whole top, front bumper/beam and rear cage with it. It's pricey but another option and it lays down very well and thick.
We've also used the base quality PPG enamel car paint on a chassis and it came out good..