Personally, I would not use paint. In my last shop of 25+ years I had stainless steel benchtops and loved them. I did some trading for them otherwise I don't know if I would have spent the money for stainless but they looked nice the entire time I had my shop and held up extremely well.
In my current shop I wanted to do the same but couldn't justify the added expense for stainless steel and ended up going 10-gauge hot rolled steel. I kept telling myself that I would remove the hot rolled mill scale but to be honest, the mill scale is so hard that it actually aids in protecting the benchtops very well.
I have only been in this shop just over 5 years now but I have had a LOT of parts and components on these benches and I have not been kind to them. They've taken it in stride.
My work benches are 30" deep with a 6" turn-up at the back and a 2" turn-down at the front.
As much as it pains me even paint supplies have been laid out on my work benches. I just put a layer of masking paper down first to give an attempt at keeping paint off of it. So far that has worked as no paint marks are visible thus far.
My fabrication table is about 20 years old and I still have not removed the mill scale from it either. The fabrication table is showing signs of the mill scale wearing off in several places though but it gets abused a LOT.
After each jobs as I'm putting tools away, I hit the benches with a rag sprayed with brake cleaner so it slowly takes the coating off but 2-3 times a year I will reapply the Sheila Shine and it brings the sheen back for some time.