You cannot go into a field of corn stalks and chisel without the coulters. Constant plugging will drive you nuts. You will have to disc the stalks first without the coulters. The coulters eliminate the need for discing first.
So if your just going to chisel plow sod or bean stibble you may get by without the coulters.
Or if you want to make two passes the noncoulter machine will work.
More equipment on the disc chisel compared to the straight chisel plow is the cost difference. Also the disc chisels are more in demand than the straight chisels so cost is higher.