As Don says, Future is common practice for making clear plastic scratchless and more realistic looking.
But its also used as a clear coating on plastic models.
As far as I know, its a water based product, that can cause bleeding on inkjet printed paper.
Its also too liquid and heavy, it will soak into paper and card very quickly.
It works when it can sit on the surface of a waterproof or non-permeable material, like on a floor...or plastic.
Only way I see it working is apply very thin coats.
Once the paper has soaked up enough, it will start sitting on the top surface, and you will be able to build up a gloss.
A solvent based clear will not hurt paper or inkjet printing.
Unless its applied too heavily, so as to 'wet' the paper.
(I use a solvent clear to seal freshly printed sheets, and on finished models to give a semi sheen. (Its also strengthens colours)
Water borne paints have solvents in them.
Water based generally don't.
Many water based products use alcohol or something similar to help speed up drying time.
I add a 50/50 water/alcohol to my acrylic paints when airbrushing.
Tip: don't buy airbrush thinner, its usually just alcohol and water (maybe with a very tiny amount of oil to lubricate the airbrush tip).
My preferred clear is lacquer clear, but Krylon sprays are the next best thing.
Solvents rule!
...
I don't know this Don, but he has some info on using Future:
Don's Airbrush Tips - Future Floor Polish
He references Dullcote Lacquer, which I also use, and works amazing on paper models!. But its very costly (small tins).