The answer is… well… that is what’s different, too. But here is a basic explanation of the differences between the two:
Rustoleum lacquer is made of polymers.
enamel is made of natural glues.
Rustoleum lacquer is usually white
enamel is usually pink or white.
enamel on your vehicle is typically an acrylic paint (or a clear lacquer)
Rustoleum is a “moldy” lacquer.
(A moldsy “lacquer” is a type of polyurethane (PU) that uses a lot of “glue” to hold it together – this glue helps hold the mold together).
Because of this “rustic” look and feel to polyurethane, the Rustoleum is sometimes sometimes referred to as “carpet” polyurethane, or “chicken glue” on the internet. Polyurethanes generally do not stick well. This is why when they are used to paint, they may come on easily, but you have to paint with a paint remover (like Securom) or an approved polyurethane paint remover (as discussed above). (And, if that fails, they can be sanded off with a cloth.)
Now, just because Rustoleum and enamel were made from the same materials, does not mean they are the same. Just from a physical standpoint, enamel is lighter in color than Rustoleum, especially if you are looking for the look and feel that comes from rust and a smooth surface. But the difference is not significant, compared to other reasons. For instance, it’s not unusual to see polyurethane painted in a semi-gloss or satin finish.
On the other hand, most people do not need to do a lot of fine tuning to get a good looking and durable vehicle with Polyurethane paint.
Rustoleum paint was sometimes known as “carpet paint” in early 2000s, and there were some good reasons for this. The early car paints were made of a mix of lacquer and polyurethane, and many of these were actually made by a single company, C-line (Carpet Company). (They closed in 2013. Not sure if they made any new products since then.) And, polyurethane paints are very good at staying on surfaces if you are painting a vehicle