aerosol bomb or a pre-mixed pt can. it's still the same product. actually the pt can paint probably is a little thicker due to less thinner in it.
to ever hope to get any durability with it you will have to have proper prep then a quality primer/ aka under coat. if you use a primer you have to sane before top coating. you need a primer, then sand when dry then e SEALER coat., then top coat.
if you skip the sealer step it won't adhere properly. NOTE if you use catalyzed epoxy primer thinned out 25% it becomes a direct to metal sealer, you just need to use multiple coats until you reach 2 mil thickness, usually 2 coats. also if you top coat before undercoat is dry, touch it without leaving fingerprint, you can create a mess.