It's fun, it's fast, cress in particular loves to be grown on paper, the seeds are mucilaginous, which means they stick to it, making it easy to water without them being washed away (other seeds splay themselves about, fall over the edge). These days we need to use food grade paper for sprouting, we traditonally used blotting paper but it contains bleaches and dyes that can leach into your sprouts. You can buy a year's supply (100 sheets) of food grade paper for only £4.20 (including postage). You can also throw other sprouts in with your cress, traditonally we used 25% mustard but also try red clover, alfalfa or brocoli. The stickiness of the cress holds them in place too.
If you don’t have much time to water, (or just forgetful) then this could be the sprouting method for you. The paper holds the water and keeps the sprouts moist, in a tray or bag, the water washes through so they dry out much faster.
They are easy to take on holiday, it’s so light to carry a couple of sheets of paper and a few seeds and stick them on a plate in your caravan or hotel room (that will surprise the chambermaid!)