I have seen them used in small gardens, but I have never used one. To be honest I would think it would really wear on your patience. Keep in mind average planting densities of soybeans is roughly a full bag per acre and corn is roughly half a bag an acre. That little hopper may run out before you plant a full row! That's going to lead to a lot of stopping and bending over and the like on your part.
For soybeans I wouldn't worry about rows. Fertilize, till, broadcast 2 directions and pack would be my method with beans. You will run over some beans when you apply herbicide later, but they will fill in - I see it all the time with ag beans. They should do just fine for feeding deer.
Corn you can try this same approach and see how it works out. Corn will typically respond the best in rows, but again we are feeding deer. Also keep in mind dent "field" corn comes in different sizes and shapes in the same bag and the plates you get with this thing may work for some and easily plug or jam. Soybeans are far more uniform in shape/size than corn - if you decide to still try the planter above.
I will be honest - a planter like above would frustrate me to know end. All that stopping and bending and walking back and forth and trying to focus on spacing to prevent smashing entire rows of corn would quickly push me to my limit and it would probably end up getting cursed a lot and then tossed into the weeds in frustration! To be honest I would suggest planting your beans the way I described and you can add in some corn if you wish (it may not produce grain but it can add to the security feel of your overall plot) - the beans will provide lots of food and you can overseed them in the fall as well with cereal grains and brassica if you wish. The ONLY advantage I see to corn (and I have planted it several times) is the security it provides along with the food itself. There are lots of other downsides to corn over beans as well. Don't get hung up and HAVING to plant corn.
if you got the route of this planter please let us know how it works out....I'm sure others have at least considered this tool.