Has anyone painted their car with rollers

Well, rolling on or spray can on paint is alot better than having a whacked out falling off paint job with different color panels and such, for most people.

In a roll on paint job, what goes on to the bare metal? Factory paint still left on in places? How is the various body repairs prepared and sealed?

A paint job is mostly about what is below the paint, how well that adheres to the metal, how well the body filler is waterproofed and corrosion proofed. Foundation that is impervious to water.

Then with the top coat, how well it is impervious to water, oxidation, chemicals, and UV, how well it will hold a shine and be resilient to abrasion?

So using a roller:

Paint is not layed out smooth in the first place, so it will be dull and irregular thicknesses. Not a big deal to some folks.

The big question is: what type of paint is being rolled on? Is it catylized? Is it solvent based? What is the durability factor to all sorts of elements? Is it designed to look and act like car paint? Modern automotive paint and clear coats are 10 fold the durability and smooth shine of rustoleum or rattle can or similar.

If you want a paint job to last well, you spend 80-90 percent of the paint job work prepping metal, working the metal, epoxy the metal, then applying body fillers, sealing and creating a smooth impervious foundation before you actually paint.

Then with all that work, rolling on rustoleum is like a finely tuned race car finished off with polyglass 14 x6 tires.

I sand blasted my neighbors hood inside and out on his 72 ford f-100 ranger. I washed it down with alcohol inside and out. Then soaked it with epoxy. While the epoxy was still hot, I did the underside with rustoleum ford blue.

But, it is an old wood hauling truck, so really it was about surface rust removal, and sealing it tight with epoxy.
I will be surprised if the rustoleum bonds correctly to the epoxy long term.