Never heard of electrophoretic coating before so went to the Googles;
"While e-coating can provide many of the same benefits, powder coating results in a thicker more durable finish. In addition, most e-coats are not UV stable, so powder coating lends increased protection to products that face exposure to the elements."
in other words they went with a cheaper, less durable option
I understood electrophoretic coating was more expensive as the chassis needs to be dipped into a tank of gloop. It also coats the inside of the tubes rather than just the bits the powder coat spray can get to.
ps before you all flame me I said "expensive" not "better" !!