First a Solvent-bourne will be best bet.
The difference between a cement epoxy is the corrosion protection is left out as far as zinc phosphates or by using different grade resins play a part also.
Where the made for, floor epoxy is better then say a car epoxy is they will use an additive so the car tires do not leave a tire print when the tires are warm and parked.
In 99 I did my wifes garage with car epoxy and I was stupid and did not put in an anti-slip that would be in a cement epoxy, for eight years if it was raining and I had on dress shoe, I would about break my a--, held up great but just redid it and added four ounces per gallon of walnut powder for an anti slip works great but now I do notice a tire marks show up once in a while and my wife will have to go out and scrub them. (its her garage, LOL)
At same time I did my play garage and I would never do that again as filler and paint just goes straight to the epoxy and it does not come off, at least with cement you can scrap off filler, instead of beating it with a hammer.
I believe the cement epoxies additive for the tires would not let the body filler stick but I'm not a 100% sure on that.