ZN and ZF could be 0.01 ticks. But ZB depth is too shallow for 0.01 tick increment. About 10 years ago they changed ZB from 1/32 ticks to 1/64 ticks but they had to revert back after a year to 1/32 because each level was too thin. There was not a multi tick wide spread as you might think, but each 1/64 level was populated with about 60 contracts. Instead of several hundred contracts when the tick size is 1/32. Basically liquidty/depth shrank because the Market Makers and scalpers didn't like the smaller spread.
How many on ET trade >60 bonds at a clip? Anyway, 1/(2^n) ticks are an accounting nuisance. Bunds trade fine in 0.01s.
T bond, notes, corn, soya, wheat, cattle, hog futures all use non decimal stuff. The exchange chief should have used decimal places right from the start. We have to live with the non decimal stuff.
But admittedly you'd have to be a fairly dimwitted American not to be able to divide, multiply, add and subtract by ten in your head. Whereas mental arithmetic in 32nds or 64ths, unless you are a professional carpenter, is not so intuitive. Let's just decimalize everything and get on with it. Or would you rather we adopted a number system in base 32 instead of base 10? That's another way to go to make arithmetic in 32nds easier.